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  1. 35 points
    Few tips and tricks to manipulate gas simulation. 1. Independent resolution grid. E.g. Overriding vel grid size independent to a density grid. 2. Creating additional utilities. E.g. gradient, speed, vorticity and etc which can be used to manipulate forces. 3. Forces via VEX and some example snippets. smokesolver_v1.hipnc P.S. Some of this technique are not Open CL friendly though.
  2. 26 points
    I want to share a little tool I made for grooming feathers. Its a set of 6 nodes, one base node and 5 modifiers. Super easy to use. Just connect them and.. there you go - you got yourself a pretty little feather. You can layer modifiers as many as you want. Any feedback is super appreciated. https://www.dropbox.com/sh/8v05sgdlo5erh0b/AADSfadqkxgPOBVeaGr2O49Oa?dl=0
  3. 24 points
    Filament like structure, combination of Smoke Solver, VDB Advect Points + Volume Rasterize Particles. smokesolver_v3.hipnc
  4. 23 points
    Another, focused on instancing smoke objects. Manipulating points with basic instancing attributes, i@cluster, v@scale and f@sourceframe. How to activate smoke object and holding a volume source. This method ideal for triggering independent gas simulation on impact data. Additional examples, e.g. grid clustering method for trail and non-trail which I'm merging from a separate thread. smokesolver_v2.hipnc
  5. 22 points
    There are so many nice example files on this website that I am often searching for. I wanted to use this page as a link page to other posts that I find useful, hopefully you will too. Displaced UV Mapped Tubes Particles Break Fracture Glue Bonds Render Colorized Smoke With OpenGL Rop Moon DEM Data Creates Model Python Script Make A Belly Bounce Helicopter Dust Effect Conform Design To Surface Benjamin Button Intro Sequence UV Style Mapping UV Box and Multiple Projection Styles Ping Pong Frame Expression Instance vs. Copy (Instance Is Faster) Particle Bug Swarm Over Vertical and Horizontal Geometry Rolling Cube Rounded Plexus Style Effect Pyro Smoke UpRes Smoke Trails From Debris Align Object Along Path Fading Trail From Moving Point Swiss Cheese VDB To Polygons Get Rid Of Mushroom Shape In Pyro Sim A Tornado Ball Of Yarn Particles Erode Surface Unroll Paper Burrow Under Brick Road Non Overlapping Copies Build Wall Brick-By-Brick FLIP Fluid Thin Sheets Smoke Colored Like Image Volumetric Spotlight Moving Geometry Using VEX Matt's Galaxy Diego's Vortex Cloud Loopable Flag In Wind Eetu's Lab <--Must See! Wolverine's Claws (Fracture By Impact) Houdini To Clarisse OBJ Exporter Skrinkwrap One Mesh Over Another Differential Growth Over Surface Rolling Clouds Ramen Noodles Basic Fracture Extrude Match Primitive Number To Point Number Grains Activate In Chunks Fracture Wooden Planks Merge Two Geometry Via Modulus Fill Font With Fluid DNA Over Model Surface VDB Morph From One Shape To Another Bend Font Along Curve Ripple Obstacle Across 3D Surface Arnold Style Light Blocker Sphere Dripping Water (cool) Exploded View Via Name Attribute VEX Get Obj Matrix Parts eetu's inflate cloth Ice Grows Over Fire Flying Bird As Particles DEM Image To Modeled Terrain Pyro Temperature Ignition Extrude Like Blender's Bevel Profile Particles Flock To And Around Obstacles BVH Carnegie Mellon Mocap Tweaker (python script) Rolling FLIP Cube Crowd Agents Follow Paths Keep Particles On Deforming Surface Particle Beam Effect Bendy Mograph Text Font Flay Technique Curly Abstract Geometry Melt Based Upon Temperature Large Ship FLIP Wake (geo driven velocity pumps) Create Holes In Geo At Point Locations Cloth Blown Apart By Wind Cloth Based Paper Confetti Denim Stitching For Fonts Model A Raspberry Crumple Piece Of Paper Instanced Forest Floor Scene FLIP pushes FEM Object Animated Crack Colorize Maya nParticles inside an Alembic Path Grows Inside Shape Steam Train Smoke From Chimney Using Buoyancy Field On RBDs In FLIP Fluid Fracture Along A Path COP Based Comet Trail eetu's Raidal FLIP Pump Drip Down Sides A Simple Tornado Point Cloud Dual Colored Smoke Grenades Particles Generate Pyro Fuel Stick RBDs To Transforming Object Convert Noise To Lines Cloth Weighs Down Wire (with snap back) Create Up Vector For Twisting Curve (i.e. loop-d-loop) VDB Gowth Effect Space Colonization Zombie L-System Vine Growth Over Trunk FLIP Fluid Erosion Of GEO Surface Vein Growth And Space Colonization Force Only Affects Particle Inside Masked Area Water Ball External Velocity Field Changes POP particle direction Bullet-Help Small Pieces Come To A Stop Lightning Around Object Effect Lightning Lies Upon Surface Of Object Fracture Reveals Object Inside Nike Triangle Shoe Effect Smoke Upres Example Julien's 2011 Volcano Rolling Pyroclastic FLIP Fluid Shape Morph (with overshoot) Object Moves Through Snow Or Mud Scene As Python Code Ramp Scale Over Time Tiggered By Effector Lattice Deforms Volume Continuous Geometric Trail Gas Enforce Boundary Mantra 2D And 3D Velocity Pass Monte Carlo Scatter Fill A Shape Crowd Seek Goal Then Stop A Bunch Of Worms Potential Field Lines Around Postive and Negative Charges Earthquake Wall Fracture Instance Animated Geometry (multiple techniques) Flip Fluid Attracted To Geometry Shape Wrap Geo Like Wrap3 Polywire or Curve Taper Number Of Points From Second Input (VEX) Bullet Custom Deformable Metal Constraint Torn Paper Edge Deflate Cube Rotate, Orient and Alignment Examples 3D Lines From 2D Image (designy) Make Curves In VEX Avalanche Smoke Effect Instant Meshes (Auto-Retopo) Duplicate Objects With VEX Polywire Lightning VEX Rotate Instances Along Curved Geometry Dual Wind RBD Leaf Blowing Automatic UV Cubic Projection (works on most shapes) RBD Scatter Over Deforming Person Mesh FLIP Through Outer Barrier To Inner Collider (collision weights) [REDSHIFT] Ground Cover Instancing Setup [REDSHIFT] Volumetric Image Based Spotlight [REDSHIFT] VEX/VOP Noise Attribute Planet [REDSHIFT] Blood Cell Blood Vessel Blood Stream [REDSHIFT] Light Volume By Material Emission Only [REDSHIFT] Python Script Images As Planes (works for Mantra Too!) Dragon Smashes Complex Fractured House (wood, bricks, plaster) Controlling Animated Instances Road Through Height Field Based Terrain Tire Tread Creator For Wheels Make A Cloth Card/Sheet Follow A NULL Eye Veins Material Matt Explains Orientation Along A Curve Mesh Based Maelstrom Vortex Spiral Emit Multiple FEM Objects Over Time Pushing FEM With Pyro Spiral Motion For Wrangle Emit Dynamic Strands Pop Grains Slope, Peak and Flat Groups For Terrains Install Carnegie Mellon University BVH Mocap Into MocapBiped1 Ramp Based Taper Line Fast Velocity Smoke Emitter Flip Fill Cup Ice Cubes Float [PYTHON]Export Houdini Particles To Blender .bphys Cache Format Collision Deform Without Solver or Simulation Mograph Lines Around Geometry Waffle Cornetto Ice Cream Cone Unroll Road Or Carpet Burning Fuse Ignites Fuel or Painted Fuel Ignition Painted Fuel Combustion Small Dent Impact Deformation Particle Impact Erosion or Denting Of A Surface Helicopter Landing Smoke And Particles Radial Fracture Pieces Explode Outwards Along Normal Tangent Based Rocket Launch Rolling Smoke Field Tear/Rip FLIP (H12 still works in H16) Rain Flows Over Surface Smoke Solver Tips & Tricks Folding Smoke Sim VEX Generated Curve For Curling Hair Copy and Align One Shape Or Object To The Primitives Of Another Object (cool setup) Useful Websites: Tokeru Houdini Houdini Vex Houdini Python FX Thinking iHoudini Ryoji Video Tutorials: Peter Quint Rohan Dalvi Ben Watts Design Yancy Lindquist Contained Liquids Moving Fem Thing Dent By Rigid Bodies Animating Font Profiles Guillaume Fradin's Mocap Crowd Series(no longer available) Swirly Trails Over Surface http://forums.odforce.net/topic/24861-atoms-video-tutorials/ http://forums.odforce.net/topic/17105-short-and-sweet-op-centric-lessons/page-5#entry127846 Entagma SideFX Go Procedural
  6. 20 points
    Hello, dear Houdniks! Realizing that at the moment I tend to code more than use Houdini at work, and not wanting to lose my edge, I made a belated New Year's resolution to try to open up Houdini every evening and do a little something, anything, every day. While at it, why not put the daily sketches up; https://dailyhip.wordpress.com/
  7. 18 points
    Hello, since last week i can play with houdini again to keep going my tests ... and bellow , some of my latest hip files from this video: torus+wrinckles+.hiplc stick man rbd+ .hiplc bubbles- rbd+cloth-2.hiplc
  8. 17 points
    During the last 3 weeks, a did some Rnd and published my results on vimeo . Some people asked me to share my files here, so here we are i hope it will help!
  9. 16 points
    Andy Lomas' work on cellular growth has been really inspiring. He implemented all his code to run on GPUs. I was wondering how hard it would be to do this natively in Houdini. After some contortions, this is what I ended up with:
  10. 15 points
    Hey guys! Here's my latest short called REACTION that I've been working on and off with for a couple of months. Enjoy! All Houdini and rendered with Octane
  11. 15 points
    Anything I can do in Houdini is thanks to the great community of people helping and sharing their knowledge. Thank you everybody, you guys rock! This is my first job done fully in Houdini (+AE) and my client let me share the source files (attached in this post). Rendered animation is here on vimeo The included network is quite simple and I hope it can help beginners to learn Houdini. I have tried to avoid slow for each loops and copy stamping, so you can find few small tricks in there. It was rendered in one afternoon on Redshift and two 1070s (cca 1.8K pixels res). And also warning: some of the effects and glows are done in AE. Used VEX if, vertexindex, smooth, rotate (matrix), setpointattrib addprim, addpoint, addvertex, removepoint user-defined functions Used CHOPs lag, math, spring, geometry, envelope, area, trigger jiggle (even for single channel) chop() expression Used VOPs dot product (to control the linear falloff), cross product primuv, volume samples VDB vdb activate, custom masked advection (clouds) nearpoint (to sample the mask advection offset) SOPs uv texture(rows&columns) to control the ramp (color&pscale) along u attribute interpolate, attribute transfer, solver polyextrude (with local controls) RedShift volume shader, light instancing point and vertex attributes odforce - project - v1.zip
  12. 14 points
    these are potential field lines drawn around positive and nevative charges. its pretty simple to implement in vex. no need for dops or pops. please take a look at the attached file and play with the settings. field_lines.hipnc
  13. 13 points
    I finally got around to cleaning up the hip file and have attached it. If you end up using this, please let me know how it's going and share a pointer to your work. The major challenge with writing this in VEX was that VEX does not offer any of the canonical data structures one would use to efficiently implement this. For me, the simulation ends up running out of memory around a 1000 frames. As I am novice to Houdini, I would also appreciate any feedback and comments you might have if you end up taking a look. Enjoy? :-) MorphogensisInVex.hiplc
  14. 13 points
    Hello everybody, i'm finishing coding a small raytracer that run in sop using vex. one of those thing I always wanted to try to do myself. it store everything on points so no rasterization plane as the idea was to have all the rendering data accessible for later use as you would with any other attributes. it is some sort of an hybrid in the sense that it is correct enough to try to make things look good. it feature many BRDF shading models, photon mapping global illumination ( mathematically done the simple way but it work) and full recursive ray's tree splitting for reflections and refractions. Here a few videos showing some of the feature and a big part of them are already available for download as an OTL for the non commercial edition for everybody interested with the hope it can be helpful to anybody that never coded those things before like me, as I learned a lot during the way. here the videos: This one have been updated recently with lots of new clips showing improvements there and there And this one got th GI part of it with a little demo at the end. download link in the description area: Hope you enjoy, best alessandro
  15. 13 points
    Just released! Here's a peek at the new features in Houdini 16 Amarok - including: a new network editor, viewport radial menus, booleans, terrain generation, auto-rigging tools, a new shading workflow and much more. Watch the live-stream this Monday, Feb 6 for a closer look! http://sidefx.co/2l1jAie
  16. 12 points
  17. 12 points
    Hello Everyone, This is a recording of the presentation I gave at the sidefx booth at GDC. Topic: Creating a custom grooming system in Houdini for VFX and Games. Chapters: --Hair grooming For VFX. --Auto generating cards with texture for Real-time rendering. --Exporting the hair for real-time rendering using Nvidia Hairworks. I hope you guys like it! If you have any questions please feel free to email me at sabervfx@gmail.com Link: https://vimeo.com/sabervfx/hairfx Thanks Saber
  18. 12 points
    Hi everyone, here are two very short clips I've created using Houdini and Mantra. I hope you like them
  19. 12 points
    i don´t know this tool but from watching the video i guess that it uses a non-rigid icp algorithm to match one geometry to another. there is no "out of the box solution" you can use in houdini but it isn´t too hard to wire together something that works in a similar way. please take a look at the attached file. it uses some pre-definded points on both geometries to guide the general alignment and deformation. if you want this to work without any user input it might become more tricky but should also be doable ... hth. petz non_rigid_icp.hipnc
  20. 12 points
    I've wanted to tackle mushroom caps in pyro sims for a while. Might as well start here... Three things that contribute greatly to the mushroom caps: coarse sub-steps, temperature field and divergence field. All of these together will comb your velocity field pretty much straight out and up. Turning on the velocity visualization trails will show this very clearly. If you see vel combed straight out, you are guaranteed to get mushrooms in that area. If you are visualizing the velocity, best to adjust the visualization range by going forward a couple frames and adjusting the max value until you barely see red. That's your approximate max velocity value. Off the shelf pyro explosion on a hollow fuel source sphere at frame 6 will be about 16 Houdini units per second and the max velocity coincides with the leading edge of the divergence filed (if you turn it on for display, you'll see that). So Divergence is driving the expansion, which in turn pushes the velocity field and forms a pressure front ahead of the explosion because of the Project Non-Divergent step that assumes the gas is incompressible across the timestep, that is where where divergence is 0. I'm going to get the resize field thingy out of the way first as that is minor to the issue but necessary to understand. Resizing Fields Yes, if you have a huge explosion with massive velocities driven by a rapidly expanding divergence field, you could have velocities of 40 Houdini units per second or higher! Turning off the Gas Resize will force the entire container to evaluate which is slow but may be necessary in some rare cases, but I don't buy that. What you can do is, while watching your vel and divergence fields in the viewport, adjust the Padding parameter in the Bounds field high enough to keep ahead of the velocity front as that is where you hope for some nice disturbance, turbulence and confinement to stir around the leading edge of the explosion. or... Use several fields to help drive the resizing of the containers. Repeat: Use multiple fields to control the resizing of your sim containers. Yep, even though it says "Reference Field" and the docs say "Fluid field..", you can list as many fields in this parameter field that you want to help in the resizing. In case you didn't know. Diving in to the Resize Container DOP, there is a SOP Solver that contains the resizing logic that constructs a temporary field called "ResizeField", importing the fields (by expanded string name from the simulation object which is why vector fields work) with a ForEach SOP, each field in turn, then does a volume bound with the Volume Bounds SOP on all the fields together using the Field Cutoff parameter. Yes there is a bit of an overhead in evaluating these fields for resizing, but it is minor compared to having no resizing at all, at least for the first few frames where all the action and sub-stepping needs to happen. Default is density and why not, it's good for slower moving sims. Try using density and vel: "density vel". You need both as density will ensure that the container will at least bound your sources when they are added. Then vel will very quickly take over the resizing logic as it expands far more rapidly than any other field in the sim. Then use the Field Cutoff parameter to control the extent of the container. The default here is 0.005. This works for density as this field is really a glorified mask: either 0 or 1 and not often above 1. Once you bring the velocity field in to the mix, you need to adjust the Field Cutoff. Now that you have vel defined along side density, this Field Cutoff reads as 0.005 Houdini units per second wrt the vel field. Adjust Field Cutoff to suit. Start out at 0.01 and then go up or down. Larger values give you smaller, tighter containers. Lower values give you larger padding around the action. All depends on your sim, scale and velocities present. Just beware that if you start juicing the ambient shredding velocity with no Control Field (defaults to temperature with it's own threshold parameter so leave there) to values above the Field Cutoff threshold, your container will zip to full size and if you have Max Bounds off, you will promptly fill up your memory and after a few minutes of swapping death, Houdini will run out of memory and terminate. Just one of the things to keep in mind if you use vel as a resizing field. Not that I've personally done that... The Resolution Scale is useful to save on memory for very large simulations, which means you will be adjusting this for large simulations. The Gas Resize Field DOP creates a temporary field called ResizeBounds and the resolution scale sets this containers resolution compared to the reference fields. Remember from above that this parameter is driving the Volume Bound SOP's Bounding Value. Coarser values leads to blurred edges but that is usually a good thing here. Hope that clears things up with the container resizing thing. Try other fields for sims if they make sense but remember there is an overhead to process. For Pyro explosions, density and vel work ok. For combustion sims like fire, try density and temperature where buoyancy contributes a lot to the motion.
  21. 11 points
    SideFX Houdini - History Houdini 16.0 2017-FEB-21 New Network Editor Brand new architecture for better performance, user experience and control Completely redesigned look and feel ‘Dot’ connections to help route wires Customizable node shapes Resizeable colour palette ‘Flyout ring’ to quickly access node flags and node info at any zoom level Persistent node info dialog with live links and cut-and-paste capabilities Visual ‘badges’ to indicate certain properties of the node Multi-selectable and multi-assignable wires Ability to knife-cut wire connections Snapping guides for fast and easy node alignment Automatic shifting of nodes to accommodate new entrants Intuitive, gesture-driven network layout tools Quickmark hotkeys to jump between networks or within one network Dimming of long wires to prevent obstruction of nodes Visual indication of non-local dependencies, with handy jump-to controls Background image support for network boxes or the entire canvas Font size, colour and background controls for sticky notes Optional display of the node type Powerful search engine Modeling Fast Boolean with exact predicates and arithmetic 3D and UV smoothing with advanced surface analysis kernels PolyFill with quads, fans, and more Enhanced PolySplit and PolyBevel Redesigned Copy/Instance and Group Intersection analysis and stitching Robust 2D triangulation Selection enhancements Fast tool access via customizable, gestural radial menus Infinite reference plane with rulers Medial axis snapping Vertex normal support in the viewport for cusping Pseudo-bevelling with Normal SOP Aggressive geometry compression Extensive OpenCL support ‘Compiled SOP’ architecture: parallel cooking and memory savings 3D Mouse support Terrain Brand new architecture for procedural terrain generation Based on height-field volumes in SOPs Full and immediate access to Houdini’s modelling arsenal 30+ dedicated surface operators Powerful erosion models Straightforward workflow, similar to image compositing but in 3D Seamless optional leveraging of Houdini’s compositing network (COPs) Ability to mask areas of interest with freeform curves and texture maps Ability to paint and override any attribute Support for geotiff and several Lidar formats Native output to game engines Fully tileable Game-friendly terrain material and specialized shader for VFX use High-quality visualization in the viewport Dedicated Mantra procedural for rendering Very fast: hardware accelerated via OpenCL Native collision support for Houdini’s physical sim environment (DOPs) Look Development Architecture for single-tiered shader creation in VOPs (no SHOPs required) - /MATs Much streamlined workflow to aid both new and existing users Full support for nested, unlimited shader layering Redesigned VOP node tiles Ray-traced SSS BSDF with image-plane outputs Support for unified nested dielectrics Dispersion and absorption BSDFs Redesigned Principled ubershader with extensive features and controls Updated shader gallery with new entries such as skin, wax and mountain Easy OpenGL tagging of shader attributes for viewport visualization Viewport support for metallics, coat, occlusion, reflection and more Texture baking enhancements OpenColor IO support Per-pixel inspection of material stylesheet overrides in IPR Significant performance enhancements to Mantra Fine-grained, intuitive controls for the quality/performance tradeoff Direct rendering of HIP files containing curves and points with no Engine license Character Many enhancements to the Animation Editor Flexible constraint architecture based on VOPs and CHOPs Biped and quadruped auto-rigs Biharmonic skin capturing to diminish the need for weight painting Fast bone placement with medial axis support ‘Invisible rig’ support in Pose tool Spring-based and FEM-based skin & muscle system Significantly improved FEM soft-body solver Optimized for performance Hair & Fur Complete overhaul of hair and fur creation, grooming and rendering Unrestricted layering of grooming operations in SOPs Rich set of dedicated tools such as clump, frizz, curl, trim, extend and part Flexible masking tools to isolate areas of interest Ability to override any attribute via texture maps or 3D paint Total freedom to mix attribute painting with 3D brushing Equal editing access to grooming guides and generated hair Full preservation of procedural graph Built-in simulation controls Easy and accurate retargeting High-quality hair visualization in the viewport Dedicated shelf tools and desktop Very fast: uses OpenCL and the new ‘Compiled SOPs’ architecture SOP-based Mantra procedural that does not consume Engine license Crowd Simulations Viewport visualization of material stylesheet overrides Animation clip layering Enhanced hip adjustment and foot locking Non-bipedal terrain adaptation Intelligent adaptation to real-time deforming terrain Advanced controls for looping, trimming and self-blending of clips Easy attachment of props such as weapons and clothing Support for custom collision shapes Robust and significantly faster computation of automatic joint limits Improved clip selection and randomization controls Clip renaming and unit conversion during FBX import Native support for collision with height-field terrain Ocean Tools Complete overhaul of the ocean FX architecture Unlimited layering of arbitrary wave spectra in SOPs Infinite oceans: tile-free approach that eliminates concern for artefacts Waves can be applied artefact-free even to deformed/warped base grids Art-directable, animated hero waves can be mixed in seamlessly Masking tools to isolate areas of interest 3D particle foam system for a richer and more realistic look Guided sims: seamless blending of FLIP fluid sim with ocean surface Improved boundary layer that preserves boundary velocities Very fast: OpenCL accelerated Layerable ocean shader that lets you plug in foam particles Render-time evaluation of ocean surface via dedicated Mantra procedural FLIP Fluids Physically correct simulation of surface tension Suction force: art-directable fluids driven by animated geometry Waterline feature: wave dynamics that extends correctly beyond boundaries Enhanced viscosity solver with slip controls Fully OpenCL-accelerated pyro pipeline Native support for collision with height-field terrains Houdini Engine & Games HAPI 3.0: no longer Houdini Digital Asset (HDA) centric; packed primitive support Remote debugger: live view and manipulation of game engine scene within Houdini Many UE4 and Unity plug-in enhancements Dedicated shelf tools for games Rigid-body and breakable simulation export to FBX Blendshape export to FBX Simulation export to textures for use in real-time engines Much improved texture baking More robust PolyExpand2D Houdini 16.0 Price (USD) as of 2017-OCT-18 Package Type Floating Floating Annual Rent Floating Annual Upgrade Plan Node Locked Node Locked Annual Upgrade Plan 30-Days Rent 7-Days Rent FX C $6,995 $4,495 $3,995 $4,495 * $2,495 $625 Core C $2,995 $1,995 $1,495 $1,995 * $995 $255 Engine C $795 $499 * $100 * $35 * Indie LC $199 ** Engine Indie LC FREE ** Education NC $75 Engine Education NC FREE Apprentice NC FREE * * Monthly Renewal * Limit of 5 Licenses per studio. ** Limit of 3 Licenses per studio. * Maximum Quantity of 5 * Maximum Quantity of 10 Houdini 15.5 2016-MAY-19 Modeling New PolyBevel 2.0 SOP New PolySplit 2.0 SOP New Dissolve 2.0 SOP TopoBuild tool (phase II) Variable width offsets in PolyExpand2D Double-click for edge loop selection Double-click for point and primitive island selection Crowds Advanced locomotion controls Direct FBX Imports for agents Vertex normal support for deforming crowd agents New Agent CHOP New Terrain Adaptation SOP Improved crowd steering behaviour Accurate foot planting Mocap Biped 3 with library of motion clips UVs Triplanar UV projection VOP Curvature support for UV Bake Tighter UV island packing in layout Lighting and Rendering Third Party Rendering Support in Houdini Indie - Today: RenderMan, Arnold, and Octane - Coming: Redshift, V-Ray and Maxwell New VR Camera built using new VR lens shader DOF and Motion Blur in OpenGL ROP Overscan rendering support and crop window fixes OpenGL displacement mapping in viewport "Render to Disk in Background" button on SOHO ROPs Photon tracing control in Mantra User Experience Better Euler tumbling in viewport 3D handle enhancements File chooser enhancements Improved geometry snapping Multi row/column pasting in Parameter Spreadsheet Help system enhancements Character "Delta Mush" deformation support Multi overlapping selection in Dopesheet Hair and fur grooming enhancements Performance Faster VEX function loading and more efficient memory use Faster saving of large geometry HQueue performance optimizations Volumes OpenVDB 3.1 Interoperability Many Alembic enhancements Houdini 15.5 Price (USD) as of 2016-FEB-06 Package Type Node-Locked Floating Subscription Houdini FX Commercial $4,495 $6,995 Perpetual Houdini Commercial $1,995 $2,995 Perpetual Houdini Engine Commercial $499 $795 Annual Houdini Indie Limited Commercial $199 --- Annual Houdini Engine Indie Limited Commercial FREE --- Annual Houdini Education Non-Commercial $75 --- Annual Houdini Apprentice Non-Commercial FREE --- Monthly Houdini 15.0 2015-OCT-15 UI GGX and PBR in viewports XML Menus Geometry PolyBridge Block Begin/End Looping Paste at cursor Animation Onion Skinning Character Picker Pane Pose Library Pane Dynamics FLIP handling 2B+ particles Crowds Rag Doll States Rendering Principled Shader (Disney) Shader Layering in VOPs Viewport Normals Material Stylesheets Update IPR Render times info Read PSDs in COPs Bake Textures Houdini 14.0 2015-JAN-15 UI Qt for GUI Visualizer New Color Picker (TMI) Animation Editor (Channel Editor) Workflow Improvements Dynamics Point Based Dynamics (PBD) Crowd Simulation Gas Curve Force Hair Grooming Material Stylesheets Bunch of New Nodes Attributes can now hold Arrays Mantra license now per-machine (previously per-CPU) Houdini Engine for UE4 2015-DEC-03 Houdini Engine for 3dsmax 2015-NOV-06 Houdini Engine 2.0 2015-OCT-15 Houdini Indie 2014-AUG-07 Houdini Engine for Cinema 4D 2014-APR-23 Houdini Engine for Unity 2013-NOV-20 Houdini Engine for Maya 2013-NOV-20 Houdini 13.0 2013-OCT-31 Particles Particles as DOPs VEX-based (Faster) Stream Concept Dynamics Finite Element Solver New Fluid Surfacer Debris Shelf Tool Packed Primitives OpenEXR 2 (ILM) OpenSubdiv (Pixar) OpenVDB (Dreamworks) Update VEX/VOP Can now create geometry Linear Workflow Data Tree Houdini Engine Introduction 2013-JUL-11 Maya Cinema 4D Houdini 12.5 2013-MAR-14 FX CloudFX OceanFX OpenVDB Sparse Volumes Primitive (Dreamworks) OpenCL DOP FLIP Animated Densities, Viscosities & Timescales Bullet Concave Geos New Bullet RBD Constraints Lighting Volume Lights Independent Env Light Workflow Alembic Updates Alembic Procedural Shader File SOP/DOP Create Dirs Geometry PolySoup Primitive Remesh SOP Wrangle Nodes UI Group visualization Coincident Points Bind VOP Houdini Master Price Drop - $4,495 2012-AUG-07 Houdini 12.1 2012-AUG-07 Edge Grouping OpenVDB Initial Integration Alembic update "Houdini FX" Naming Orbolt Smart Asset Store Tetra Primitives Houdini 12.0 2012-MAR-01 Simulations Faster (Pyro, Cloth, FLIP, Hair/Fur) FLIP Viscosity PyroFX 2.0 Re-written core OpenCL/GPU simulation Clustering Pyro Shader SOP Solver Bullet (now default) RBD Rendering PBR for Volumes IES Lights OpenGL ROP Point Instance Procedural Shader Viewport Rewrite - OpenGL 3.2 Performance Monitor New geometry core (GA library replaces GB library) Houdini Master Price Drop - $6,695 2010-JUN-10 Houdini 11.0 2010-JUL-27 Simulations FLIP Solver - See History Dynamic Fracturing (Voronoi) SPH Speed Up Improvements on Fur/Cloth Volume Nodes Shader Building Material Shader Builder Delayed Load Procedural VOP Ptex Uniform Volume Property (PBR/RT) VOPs Shader Effects Collapse/Peg Debug/Bypass Viewport OpenGL Effects (Volumes, Lights, Normals) 11.1 Alembic Support Extended Support for OpenEXR & Field3d Houdini 10.0 2009-APR-16 Simulations Distributed Sims Smoke Up-res Rendering Progressing Interactive Photo-realistic Rendering (IPR) PBR Multi-threading Engine now implemented in VEX Deep Camera Maps Dynamics RBD - ODE Cloth Crumpling/Tearing Misc Stereo Support Sticky Notes Shaking Disconnect Shift/Ctrl movement shortcuts MotionFX Houdini Apprentice HD - $99 2008-JUN-12 Houdini 9.0 2007-SEP-20 Fluid Dynamics Solver Liquids Smoke & Fire (PyroFX) New User Interface Tool Shelf Parameter Interface Mantra PBR & Volume Rendering Volume Primitives Python Support 9.5 Mac Support (2008-JUN-12) FBX Export Houdini Master Price Drop 2007-MAR-01 Floating: $9,995 Node Locked: $7,995 Houdini 8.0 2005-OCT-06 New Dynamics Architecture DOPs Light Linking and Interactive Photorealistic Rendering (IPR) Character Workflow Improvements Irix Support Discontinued Disney's The Wild, C.O.R.E. (3 Years - 2006-APR-20) 8.1 Auto Rig Muscle Houdini Master - $17,000 2005-OCT-06 Package Floating Node-Locked Houdini Select $1,299 $1,599 Houdini Halo --- $2,999 Houdini Escape $1,999 $2,999 Houdini 7.0 2004-SEP-20 Takes Manager RSL VOPs Channel List / Dope Sheet Documentation File Loading Free HDK Houdini Escape (Model, Anim, Texture, Light, Render) - $1,999 RenderMan Support Character Tools Improvements Houdini 6.0 2003-MAY-08 Digital Assets (OTLs) 6.1 UV Pelt (2003-JUL-23) Syflex Plugin (2004-FEB-09) - $2,200 Character Workflow Improvements Houdini Master 2002-JUN-28 Houdini Halo (Comp) 2002-JUN-22 Houdini Escape (Character) 2002-JUN-22 Houdini Apprentice 2002-JUL-09 Houdini - $15,999 2002 Houdini Select - $1,299 2002 Houdini 5.5 2002-MAY-14 64-Bit Support [*] New COPs (COP2) Deep Raster VOPs Major new Character Tools Houdini Community Section on website X-Men 2 BAMF - Vijoy Gaddipati, Lead FX TD, Cinesite. (Released 2003-MAY-6) Houdini 5.0 2002-MAR-12 Mental Ray (2001-JUL-11) Viewport Modeling Solaris Support (Later dropped) Houdini Select - $1,999 2001-AUG-13 Houdini 4.0 - $17,000 2000-JUL-24 [*][*][*] Resizable Panes VEX (Mark Elendt) [*] Mantra Updates Linux Port [*] 4.1 TouchDesigner was derived from this version. [*] Houdini 3.0 1999-OCT-02 [*] Motion Capture (Mouse, Keyboard peripherals) Subdivision Surfaces Higher Order Rational Curve Networks WREN Houdini 2.5 1998-MAR-28 [*] POPs CHOPS Windows NT Port Houdini 2.0 1997-AUG-05 [*] UI Enhancements Four View Modeller Advanced OpeGL Display (Transparency & Projected Spotlights) Mantra 4 Fast Motion Blur Lens Flare Built-in Network Rendering Modeling Surface Pasting Animated Trim Curves Nested Intersection Trim Loops Clay Tool Sleletal Capturing and Deformation Tools Operator Subnetworks Houdini 1.0 - $9,500 1996-OCT-02 [*] First Non-linear 3D Environment (Procedural) 3D and 2D tools Integration Nurbs RenderMan Front-end Scripting and Expression Language PRISMS Short History [*] Execellent Review of Prisms, includes lots of screenshots! [*] DATE VERSION UPDATES 1998 PRISMS 7.0 Final Ship 1997 PRISMS 6.4 SGI O2 Compatibility 1997 PRISMS 6.3 RenderMan Interface 1996 PRISMS 6.1 Optimizations (Houdini 1.0 at SIGGRAPH) 1995-JUN PRISMS 6.0 Introduction of Sage, the node-based package for modeling. This was the prototype of Houdini. 1995-JAN PRISMS 5.5 L-Systems 1994-JUN PRISMS 5.4 MOCA, TIMA 1993-DEC PRISMS 5.3 MOJO, ICE, Metaballs 1992 PRISMS 5.2 FPaint Added (new C++ UI libs) 1991 PRISMS 5.1 Full-width Graph 1991 PRISMS 5.0 Crystal2 Renderer Eliminated 1991 PRISMS 4.5 Particles 1990 PRISMS 3.0 Mantra Raytrace Renderer Added 1989 PRISMS 2.0 Patch Support, Deformation SOPs 1988 PRISMS 1.5 Initial SOPs, Light Editor 1987 PRISMS 1.0 New motion editor and modeler combined to form action. Installer File Sizes * I set some parts to BOLD to emphasize particular version highlights. * References: Google, OdForce Wiki, SideFX Press, Houdini Help Docs, CG Channel, CG Press, Nekochan. * For those interested, I also posted a Houdini FLIP History blog post here.
  22. 11 points
    HI FRIENDS! So over the past year I've been doing far too much Houdini in my free time, and I noticed that all of the people I look up to in the community have their own cute ODForce threads. So with the release of my latest blog post on Voronoi Diagrams and Remeshing, I thought it best to make one of those threads, to avoid flooding the Education section with tons of new posts... Anyways here's a link to my new blog post: https://medium.com/@jakerice_7202/voronoi-for-the-people-60c0f11b0767 And if the link itself isn't enough, here are a couple of GIFs from the blog post, including one that didn't make the cut. All credit for the post title goes to @mestela <3 Big thanks to @toadstorm for editing my grammar as well, and the whole ThinkProcedural discord for putting up with my insanity
  23. 11 points
    I am not sure if this has been posted before but just came across this site: http://wordpress.discretization.de/houdini/ To quote: "This website is here to help you to get started with Houdini in order to complete the Mathematical Visualization course at the Technical University of Berlin. The aim is to enable you to run your own geometry related algorithms while taking advantage of Houdini’s excellent visual graphics while avoiding to dig deep into the theory behind it." There seems to be some great material on here. In particular a unique way of getting scipy/numpy to work with Houdini - apparently you just copy and paste the entire anaconda 2.7 build into the Houdini python directory?! http://wordpress.discretization.de/houdini/home/advanced-2/installing-and-using-scipy-in-houdini/
  24. 11 points
    hey all thought i'd just drop a grenade of Houdini work i put together over 2016 & early 2017 - nothing particularly complex - most of this is all stuff i've learnt off this forum and youtube video tutorials by ppl like @mestela @ParticleSkull @Farmfield @rohandalvi the guys at Entagma, Sidefx, and a bundle of other ppl whom i cant seem to tag like Ben Watts - i just want to say thankyou for all your help and tutorage on forums and the time you guys take to put all those epic videos together and encouraging me to learn cheers ant hoob (houdini noob geddit?!) this was my first project set in houdini - following tutorials and clearly inspired by Method (who isn't c'mon) and their video.. I then went away and did some more twiddling with sop based stuff to try some more fun effects - had alot of fun with this one - i love balloon boy lol... this was inspired by all the Hydraulic press channels and just trying a fun few setups... this one was inspired by Erik Fergusons fem stuff... and this one was an attempt to try some fun ragdoll/crowd sim stuff :)
  25. 11 points
    Hi friends! I just released an article on Medium walking through how I built a "Compute Dual" wrangle in VEX. As a quick summary, I basically wanted to know how the "Compute Dual" feature of the divide sop worked, so i slapped together a neat lil wrangle, to do just that! CLICK ME TO GO TO THE ARTICLE!!!!!!!! Here's a cute little gif showing off the construction of a dual graph. If you like it, please check out the article, it's free and it'd mean the whole world to me! =) Love you fools, Jake http://jakericedesigns.com/
  26. 11 points
    Teaser trailer is out now! Lots still left to do, but things are coming together.
  27. 11 points
    Thank you ! Here it is the zip file including PDF and all the hip files with the ink setup and tornado setup. The scene files have been created with Houdini 15.5.632. Enjoy ! Hug_Nov2016-AlessandroPepe.zip
  28. 11 points
    Coarse Sub-Steps If you have an expanding gas field front that from frame 1 to 2 or frame 2 to 3 travels one or two Houdini units and substeps are set to 1, you will get combed straight velocity vectors which means mushroom caps. No matter how much turbulence or confinement you set on your Pyro Solver DOP, there simply isn't enough time to evolve these fields and have an effect on the result. More substeps means smaller velocities to deal with between substeps making things more manageable too. In an attempt to keep substeps at 1, you can manufacture noise and pump that in to vel but in the end two things will happen: The Non-Divergent step will take your noise and negate most of it, or you end up pumping in so much noise because it isn't working with smaller values you tried earlier, that it swamps the entire effect and it looks like a fractal hash and not that nice evolving fireball. Oh and if you really pump in tons of noise in to vel, it too can create many smaller velocity fronts pushing ahead and you end up with smaller mushroom caps! Doh... This is in essence what the Gas Disturbance DOP does. The Pyro Solver has a Gas Disturbance DOP in it's logic and those parameters are promoted up to the top asset interface but we're concerned about substeps right now and allowing enough time for turbulence and confinement to create the nice swirls on the leading edge of the explosion. So it's coming down to sub steps to try and allow for a lot more character around the leading pressure front for fast evolving explosion type simulations. Two ways to go about this: Brute force increase the global substeps for the entire DOP network, or use the Pyro Solver Substeps in the Advanced tab. Brute Force Global Substeps For explosions, the huge almost instantaneous velocities happen at the first 5-10 frames. It would be nice to keyframe animate the Sub Steps parameter, but you can't (DOPs is that way). If you set the global sub-steps to get enough detail in the first few frames you have to carry those sub-steps through the rest of the sim when things are moving a lot slower and those substeps are no longer required. Not that great. No wonder everyone tries to inject their own pumps to affect vel to avoid global substepping. Pyro Solver Substeps The Pyro Solver exposes minimum and maximum substepping logic to control when and how the Pyro Solver will substep. This sounds interesting and could be just what we need. But what is CFL Condition? No it isn't the Canadian Football League even though we know that 3 downs rule and 4 downs are for those that can't deal 3. It's named after a couple guys who in the '20's, that's 1920's, who were trying to figure out the frequency of data samples they required in order to map and predict fluid simulations and pressures/resistance to flow with fast moving collision objects (that be ships). The help note on the actual Gas SubStep DOP explains it quite well: timestep will be reduced if the velocity field will move only 1 voxel in a timestep. A CFL of 2 will allow it to move 2 voxels in a timestep. Or something like that. You can find it on wikipedia. You can set your minimum substeps to 1 and your maximum substeps to a high enough value such that if the CFL Condition is exceeded, more substeps will occur when the simulation has large velocities and less when the velocity is smaller. Hopefully this gives enough time to let the turbulence and other methods to stir up the vel field kick in. Keyframe Timescale There is a third option to controlling sub steps but that is to keyframe animate the Timescale. Yes more than valid to do this to slow down the sim at the start and then speed up when the huge velocities subside. As a matter of fact, the shelf tools set Timescale to 0.65 as an attempt to get a good looking explosion or fireball without having to resort to substeps. But this is not an automatic method. This requires intervention if you want to animate the timescale. This means you have to run the sim and evaluate. Then you keyframe the timescale and you end up with an entirely different simulation. Then you move your keys, run again. Then you increase the resolution of the simulation and everything changes again. In many ways, it's worth to at least give the min and max substeps a go and see if you can dial in the CFL Condition to get a happy balance. As you increase the resolution of the simulation, the CFL condition measured in voxels will allow substeps to run up a bit faster to the max without too much of a change in the final result.
  29. 10 points
    Hi, I played around your scene a bit. This is the result. I also ended up changing your extrusion expression using exp() instead of pow(). The gist of it was to do 2 iteration phases. 1 is ahead, and the other is behind. Then just blend between those two. The challenging part was to create the attributes needed to specify the iteration level, and the blending amount (check the blend_and_iter wrangle node for how I processed it). Although this seems to chug to slow when there's already too many polygons to process. I wanted to place it inside a compiled block, but polyExtrudes are not yet compilable. H16.5.268 NC - Subdiv_Test_v2.rar
  30. 10 points
    Hey, thought I'd share this here. Preview of tree and foliage creation and layout tools now available on Gumroad. I've released them as "pay what you want" as my contribution to the community. I plan to keep supporting and improving these tools in future as well as releasing other tools. Let me know if you have any feedback/suggestions and I look forward to seeing what people create with them. Enjoy! https://gumroad.com/l/zWFNX
  31. 10 points
    some other files from "softbody- week3" video to understand how to mimic interaction between rbd/cloth , pyro/cloth, how to play with attributes and multisolver like @massdensity. same way for fluid/cloth interaction and other attributes used in the video. ++ cloth+pyro.hipnc blob+boxes-shellmassdensity.hipnc blob-shellmassdensity.hipnc
  32. 10 points
    The main thing you can learn from these types of things is the art of self promotion
  33. 10 points
    I wanted to see if I could play a video in Houdini using some python. With this as the result. Don't think it's the first time this is done but it is still nice to see. The result
  34. 10 points
    Here is collection of breakdowns for a project I was working on during last half of a year Vimeo album: https://vimeo.com/album/4471569 Or individual videos:
  35. 10 points
    I think Cristin mentioned it in the launch event, but but in case anyone missed it: Nearly all the areas presented in H16 will continue on into the next dev cycle. That's not to say other projects won't be started, just that we'll be building on the cool stuff presented in H16.
  36. 10 points
    Hello everybody, I want to share with you small tool I created recently using VEX. I wanted to create wall made of non-uniform stones (with different widths and also heights). Solutions I found here are really great but I thought I might push it a bit further. I figured out algorithm that can produce such pattern. It can be customized to fit desired look. Besides it runs pretty fast compared to voronoi approach Attached test renders were done using Techie's amazing rock generator that can be found here: http://www.orbolt.com/asset/Techie::rock_generator::1.0 Have a nice day Peter pt_stone_pattern.hdalc
  37. 10 points
    Short answer is no. I think you're missing a lot of computer history. Linux (1991) was influenced by Unix (1971). In fact, Linux (as the whole ecosystem, not just the kernel) is one of many variants descended from Unix. One other important Unix descendant was IRIX (1988) which ran on the graphics workstations made by Silicon Graphics (SGI) (1982). Houdini (1996) was the successor to PRISMS (1987). So all these particular commands that you're talking about are actually Unix commands, not Linux. PRISMS and Houdini used to run on IRIX on Silicon Graphics workstations, as did Maya (1998) and its predecessors. Today, most of the big 3d studios (like Pixar, Disney Animation, DreamWorks, Blue Sky, ILM, Framestore, etc) all run Linux because they used to run IRIX. Windows (1993) as you know it today wasn't used much for 3D work until the computer games industry took off. CLI in general has been around since the dawn of operating systems. Interestingly, the "ls" Unix command was an abbreviation of the "list" Multics (1964) command, which itself was a shortened form of the CTSS (1961) "listf" command (according to A Brief History of the 'ls' Command). And to complete the OS history lecture, Windows can be seen as a descendant of VMS (1977) since it was largely designed by the same developers (who had been hired away from DEC by Microsoft). And VMS of course drew inspiration from Multics amongst other OSes.
  38. 10 points
    There was an error in pop_too_close wrangle. It deleted both intersecting bubbles, not just the smaller one, drastically reducing bubblecount. Normally it should remove only degenerate bubbles almost enclosed by neighbours. It also seems that whole loop can be replaced with a point wrangle. So, it cooks instantly now, retains topology and scales better. Scattering and pscale setup really matters. You need to generate a good foam first, before doing intersections. The current setup should be improved somehow. bubbles2.hipnc
  39. 9 points
    Hi all, I had been doing a rnd project on how to generate knitted garments in Houdini lately. And one my inspiration was from a project which was done by Psyop using Fabric engine and the other one is done by my friend Burak Demirci. Here are the links of them. http://fabricengine.com/case-studies/psyop-part-2/ https://www.artstation.com/artist/burakdemirci Some people asked to share my hip file and I was going to do it sooner but things were little busy for me. Here it is, I also put some sticky notes to explain the process better, hope it helps. Also this hip file is the identical file of the one that I created this video except the rendering nodes https://vimeo.com/163676773 .I think there are still some things that can be improved and maybe done in a better way. I would love to see people developing this system further. Cheers! Alican Görgeç knitRnD.zip
  40. 9 points
  41. 9 points
    [SIGGRAPH 2017] Anisotropic Elastoplasticity for Cloth, Knit and Hair Frictional Contact
  42. 9 points
    Hey everyone! Here's a demo of some point cloud tools I created to calculate concave and convex curvature as well as gradient and curl direction, also sharpening. Forgot to mention in the demo that the curvature calculation is a great way to do differential growth by advection along normal * curve * noise * parm. Also, the curl calculation can be used to make grass patches and groom fur by orienting curves along the direction to add swirly variance. There's a lot of ways these tools can be handy, interested to see what you all come up with! Let me know if you have any questions, enjoy! curveGradientCurlSharpen_v002.hipnc
  43. 9 points
    Hello, I've revamped this thing in H16. Basically it's same, just changed a long distance geometry query to VDB sampling, it seems to fits best. Also added some auxiliary functionalities, like reversing polygons if needed, uv creation and such. It's created by H SOP and VOP arsenal. Get hiplc here. How it works: First step is volume sample of VDB representation of another mesh. Sampled SDF is saved as float attribute, zero SDF is used by PolyCut SOP to create intersection curve. Final offset Cuts on meshes are also PolyCut SOP done by spatial query, XYZ Distance VOP and such. Intersection curve is re-sampled down and converted to NURBS, to get as much smooth fillet. From that curve, there's spatial query to cuts on meshes, to get closed points. In next step, curve is re-sampled again to final fillet resolution, also there's new spatial query to cuts, this time only to match the final position, while orientations are derived from low res curve. This is to avoid 'bulging', invoked by linear cuts over polygons. Last step is six point bezier curve, well known as G2 blend in NurbS world, used to loft the fillets, by Skin SOP. More specific, what it can and can not do: - it automatically creates NURBS style fillets around intersections of two polygon meshes. - it wants two closed meshes as inputs, while second mesh has to be perfectly closed (no boundary edges) - will see is there a simple way to improve that. - it is able to perform fillets over fillets - only in case of closed second input. - it is able to deal with multiple intersections, or multiple (closed) volumes, let's say created by Merge SOP. - it creates fillets from union, intersection or subtraction. Default is union. - it creates UVs on fillets. If there are existing UVs on inputs, H will keep them. - it aligns normals (or exactly, vertex order) of created fillet, to first input. - each intersection has to be 'closed', that is, resulting in closed curve, in order to work properly. - meshes has to be nicely subdivided before inputs. It's just cutting over supplied inputs, it won't create new, smaller polygons. - it does not work well with sharp curvature - will see is there a way to improve that. - fillets should not overlap. - resulting meshes are just stacked, there is no any re-meshing, at this point.
  44. 9 points
    Thank you @MrScienceOfficer ! Here's one I did today
  45. 9 points
    Nuke-like way to change the parameter values with keyboard- you can move the value up and down with the up and down arrow keys
  46. 9 points
    Hello, I am putting my experiments and RnD here: http://lab.ikoon.cz/ Maybe you will find some inspiration there. Source files and URLs are included.
  47. 9 points
    This is really cool... Looking to the very first part, I did a simple setup yesterday, trying to replicate it, but can't say I got very far before running into issues. The problem with the POP setup is it really wants to create the coral patterns - even using a polyframe to calculate outwards normals and using them to guide velocity outwards, you get to a point where is starts to fold into itself" and create those traditional differential curve type patterns... So perhaps something ti rethink - or perhaps someone here has an idea..? Oh, and just generally, there's SOOO much friggin cool stuff in this video, I can barely watch without freaking out, wanting to try to replicate all of them, hehe...
  48. 9 points
  49. 9 points
    Project Non-Divergent Step and Mushrooms The Project Non-Divergent DOP is responsible for 99.9% of the simulation's behaviour. Yes hundreds of DOPs inside the Pyro Solver all playing a part but all funnelling through that single Non-Divergent step. This means that if you don't like the look of your sim and the mushrooms, it's ultimately because of the Non-Divergent step creating a vel field that doesn't do it for you. If you want to see for yourself, unlock the Pyro Solver, dive in, find the Smoke Solver, unlock that, dive in and find the projectmultigrid DOP and bypass it, then play. Nothing. For most all Pyro sims, this is the Project Non-Divergent Multigrid as it is the fastest of the Non-Divergent micro-solvers. This specific implementation only takes the vel and divergence field and assuming across the timestep that the gas is non-compressible when divergence is 0, will create a counter field called Pressure and then apply that pressure field to the incoming vel to remove any compression or expansion and that gives you your velocity, nice turbulent and swirly, or combed straight out. Just tab-add a Project Non-Divergent Multigrid DOP in any dop network and look at the fields: Velocity Field, Goal Divergence Field and Pressure Field (generated every timestep, used, then removed later on). All the other fields in Pyro are there to affect vel and divergence. Period. Nothing else. At this point I don't care about rendering and the additional fields you can use there. It's about vel and divergence used to advect those fields in to interesting shapes, or mushrooms. If you want to create your own Pyro Solver taking in say previous and new vel, density, temperature, and then in a single Gas Field VOP network, create an interesting vel and divergence field, then pass that straight on to the Project Non-Divergent Multigrid microsolver, then advect density, temperature and divergence afterward, go for it. Knowing that only vel and divergence drive the simulation is very important. All the other fields are there to alter the vel and divergence field. So if you have vel vectors that are combed straight, divergence (combustion model in Pyro) or buoyancy (Gas Buoyancy DOP on temperature driving vel) have a lot to do with it. Or a fast moving object affecting vel...
  50. 9 points
    There is no mystery as to how Houdini works. Anything that gets done in Houdini can be expressed by a node. Whether that node is a coded c++ operator, an operator written in VEX (or using VOP nodes representing vex functions), Python operators or Houdini Digital Assets (HDA's), each node does it's own bit and then caches it's result. There is no lower level than nodes. The nodes in Houdini are the lowest level atomic routine/function/programme. A SOP node for example takes incoming geometry and processes it all in of itself, then caches it's result which is seen in the viewport, MMB on the node as it's stats and in the Details View to see the specific attribute values. If this is a modifier SOP, it will have a dependency on it's input node. If there is an upstream change, the current node will be forced to evaluate. If there is a parameter reference to another node and the other node is marked "dirty" and affects this node, this node will have been forced to evaluate. To generalize the cooking structure of a SOP network, for every cook (frame change, parm change, etc), the network starts at the Display/Render node and then walks up the chain looking for nodes with changes and evaluates dependencies for each node also querying those nodes for changes until it hits the top nodes. The nodes marked dirty causing the network to evaluate the dirty nodes top down evaluating the dependencies that were found. You can set a few options in the Performance Monitor to work in the older H11 way and see this evaluation tree order if you wish. Change that. It is "mandatory" that you do this if you want a deeper understanding of Houdini. You definitely need to use the Performance Monitor if you want to see how the networks have evaluated as it is based on creation order along with the set-up dependencies. Yes deleting and undeleting an object can and will change this evaluation order and can sometimes get you out of a spot with crashing. If you haven't used the Performance Monitor pane, then there you go. Use it. Just remember to turn it off as it does have an overhead performance wise. Another key is to use the MiddleMouseButton (MMB) on any and all nodes to see what they have cached from the last cook evaluation. Memory usage, attributes currently stored, etc. the MMB wheel on my mouse is as worn in as the LMB as I use it so much. You can see if the node is marked as time dependent or not which will affect how it evaluates and how it will affect it's dependent nodes. You can RMB on the node and open up the Dependency view for that operator which will list all references and dependencies. You can hit the "d" key in the network and in the parameter display options, in the Dependency tab, enable the various dependency aids (links and halos) in the network to see the dependencies in the network. Houdini is a file system, in memory, and on disk in the .hip "cpio" archive file. If you want, you can use a shell, and given any .hip file, run the hexpand shell command on the file. This will expand the Houdini file in to a directory structure that you can read and edit if you so wish. Then wrap it back up with hcollapse. If you really want to see how Houdini works low level, then this how it all ends up, and how it all starts. It's just hscript Houdini commands that construct the nodes including the folder nodes themselves. Each node is captured as three distinct files: the file that that adds the node and wires it up to other nodes, the parameter file that sets the nodes parameters, and another file that captures additional info on the node. If you locked a SOP, then that binary information will be captured as a fourth file for that node. It is for this reason that .hip files are very small, that is unless you start locking SOPs and that is not wise. Better to cache to disk than lock but nothing stopping you. When you open up a .hip file, all the nodes are added, wired, parameters modified and nodes cooked/evaluated. There are different types of node networks and nodes of a specific type can only be worked on in specific directory node types. This forces you to bop all over the place, especially if you still willingly choose to use the Build desktop which I do not prefer. You have to have a tree view up somewhere in the interface to see how the network lays out as you work. It's also very handy for navigating your scene quickly. The Technical Desktop is a good place to start when working on anyone's file as there is a tree view and a few other panes such as the Details View, Render Scheduler and more. If you want to use the technical desktop and follow a vid done with the Build desktop, simply switch up the Network with the Parameter pane and now the right hand side is the same as Build, but now you can follow the tree view and see where and when other nodes are dropped down. A new Houdini file is an unread book, full of interesting ideas. Using a desktop that exposes a tree view pane, you can quickly see what the user has been up to in a couple seconds. Again use the Technical Desktop as a start if you are still using Build (if you know me you will know I will force you to have a tree view up). You can quickly traverse the scene and inspect the networks. If that isn't enough, you can pop open the Performance Monitor and see what nodes are doing the most work. You really don't need any videos, ultimately just the .hip file. Helps if the scene is commented and nodes named based on intent. Let's stick to SOPs. In Houdini, attributes are an intrinsic part of the geometry that is cached by each SOP. Not some separate entity that needs to be managed. That is what makes SOPs so elegant. That wire between two SOPs is the geometry being piped from one SOP to the next, attributes and all. Not a link per attribute (which in other software can be a geometry attribute, parameter attribute, etc). This makes throwing huge amounts of geometry with lots of attributes a breeze in Houdini. All SOPs will try their best to deal with the attributes accordingly (some better than others and for those others, please submit RFE's or Bugs to Side Effects to see if there is something that can be done). You can create additional geometry attributes by using specific SOPs: - Point SOP creates "standard" point attributes - Vertex SOP creates "standard" vertex attributes - Primitive SOP creates "standard" Primitive attributes - Use the Attribute Create SOP to create ad-hoc attributes with varying classes (float, vector, etc) of type point, vertex, primitive or Detail. - Use VEX/VOPs to create standard and ad-hoc point attributes. - Use Python SOPs to create any standard or ad-hoc geometry attributes. One clarification that must be made is the distinction between a "point" and a "vertex" attribute in Houdini. There are other softwares that use the term vertex to mean either point attributes or prim/vertex attributes. Games have latched on to this making the confusion even deeper but alas, it isn't. In Houdini, you need to make the distinction between a point and a vertex attribute very early on. A point attribute is the lowest level attribute any data type can have. For example, vector4 P position (plus weight for NURBs) is a point attribute that locates a point in space. If you want, that is all you need: points. No primitives what so ever. Then instance stuff to them at render time. You can assign any attribute you want to that point. To construct a Primitive, you need to have a point for the primitive's vertices to reference as a location and weight. In the case of a polygon, the polygon's vertices is indexing points. You can see this in the Details View when inspecting vertex attributes as the vertex number is indicated as <primitive_number>:<vertex_number> and the first column is the Point Num which shows you which point each vertex is referencing as it's P position and weight. Obviously you can have multiple vertices referencing a single point and this is what gives you smooth shading by default with no vertex normals (as the point normals will be used and automatically averaged across the vertices sharing this point). In the case of say a Primitive sphere, there is a single point in space, then a primitive of type sphere with a single vertex that references that point position to locate the sphere. Then there is intrinsic data on the sphere (soon to be made available in the next major release) where you can see the various properties of that sphere such as it's bounds (where you can extrapolate the diameter), area, volume, etc. Other primitive types that have a single point and vertex are volume primitives, metaball primitives, vdb grid primitives, Alembic Archive primitives, etc. How does a Transform SOP for example know how to transform a primitive sphere from a polygonal sphere? Answer is that it has been programmed to deal with primitive spheres in a way that is consistent with any polygon geometry. Same goes for Volumes. It has been programmed to deal with Volumes to give the end user the desired result. This means that all SOPs properly coded will handle any and all primitive types in a consistent fashion. Some SOPs are meant only for Parametric surfaces (Basis SOP, Refine SOP, Carve SOP, etc.) and others for Polygons (PolySplit, etc.) but for the most part, the majority of SOPs can work with all primitive types. What about attributes? The Carve SOP for example can cut any incoming polygon geometry at any given plane. It will properly bi-lineraly interpolate all attributes present on the incoming geometry and cache the result. It is this automatic behaviour for any and all point, vertex, primitive and detail Attributes that makes working with SOPs a breeze. How does Houdini know what to do with vertex attributes when position P, velocity v and surface normal N need to be handled differently? When performing say a rotate with a Transform SOP and the incoming geometry has surface normals N, velocity vector v, and a position cache "rest", each attribute will be treated correctly (well N because it is a known default attribute but for user-defined attributes, you can specify a "hint" to the vector that will tell it to be either vector, 3 float position, or of type surface normal). It is this auto-behaviour with attributes and the fact you don't need to manage attributes makes using SOPs so easy and very powerful without having to resort to code. Remember that each SOP is a small programme unto it's self. It will have it's own behaviours, it's own local variables if it supports varying attributes in it's code logic, it's own parameters, it's own way of dealing with different primitive types (polygons, NURBs, Beziers, Volumes, VDB grids, Metaballs, etc). If you treat each SOP as it's own plug-in programme, you will be on the right path. Each SOP has it's own help card which if it is authored correctly will explain what this plug-in does, what the parameters do, what local variables are available if at all, some other nodes related to this node, and finally example files that you can load in to the current scene or another scene. Many hard-core Houdini users picked things up by just trolling the help example files and this is a valid way to learn Houdini as each node is a node and a node is what does the work and if we were to lock geometry in the help cards the Houdini download would be in the Gigabytes so nodes are all that is in the help cards and nodes is what you need to learn. I'm not going to touch DOPs right now as that is a different type of environment purpose built for simulation work. Invariably a DOP network ends up being referenced by a SOP to fetch the geometry so in the end, it is just geometry which means SOPs. Shelf tools are where it's at but I hear you. Yes there is nothing like being able to wire up a bunch of nodes in various networks and reference them all up. Do that for a scratch FLIP simulation once or twice, fine. Do that umpteen times a week, well that is where the Shelf Tools and HDA's make life quite simple. But don't be dismayed by Shelf Tools. All of those tools are simply executing scripts that place and wire operators together and set up parameter values for you. No different than when you save out a Houdini .hip scene file. If you are uber-hard-core, then you don't even save .hip files and you wire everything from scratch, every time, each time a bit different, evolving, learning. So with the shelf tool logic you find so objectionable, if you open up an existing .hip scene file, you are also cheating. Reminds me of the woodworker argument as to what is hand built and what isn't. I say if you use anything other than your teeth and fingernails to work the wood, you are in essence cheating, but we don't do that. Woodworkers put metal or glass against wood because fingernails take too long to grow back and teeth are damaged for ever when chipped. And I digress... Counter that to power users in other apps that clutch to their code with bare white knuckles always in fear of the next release rendering parts of their routines obsolete. With nodes, you have a type name and parameter names. If they don't change from build to build, they will load just fine. I can load files from before there were .hip files and they were called .mot (from Sage for those that care to remember) from 1995. Still load, well with a few meaningless errors but they still load. A Point SOP is a Point SOP and a Copy SOP is a Copy SOP. No fear of things becoming obsolete. Just type in the "ophide" command in the Houdini textport and you will still find the Limb and Arm SOPs (wtf?). LOL! First thing I do every morning? Download latest build(s). Read the build journal changes. If there is something interesting in that build, work up something from scratch. Then read forums time permitting and answer questions from scratch if I can. All in the name of practice. Remember from above that a .hip file is simply a collection of script files in a folder system saved on disk. A Houdini HDA is the same thing. A shelf tool again is the same thing: a script that adds and wires nodes and changes parameters. Not pounding a bunch of geometry and saving the results in a shape node never to have known the recipe that got you there. To help users sort out what created which node, you can use the "N" hotkey in any network and that will toggle the node names from the default label, the tool that added that node and finally nothing. Hitting "N" several times while inspecting a network will toggle the names about. That and turning on the dependency options in the network will help you see just what each shelf tool did to your scene. Knowing all this, you can now troll through the scene and see what the various shelf tools did to the scene. If you like to dig even deeper, you can use the Houdini textport pane and use the opcf (aliased to cd), opls (aliased to ls), and oppwf (aliased to oppwd and pwd) to navigate the houdini scene via the textport as you would in a unix shell. One command I like to show those more interested in understanding how Houdini works is to cd to say /obj then do an opls -al command to see all the nodes with a long listing. You will see stats very similar to those found in a shell listing files or if you RMB on any disk file and inspect it's info or state. Remember Houdini "IS" a file system with additional elaborate dependencies all sorted out for you. There are user/group/other permissions. Yes you can use opchmod (not aliased to chmod but easily done with the hscript alias command) to change the permission on nodes: like opchmod 000 * will remove read/write/execute permissions on all the nodes in the current directory and guess what? The parameters are no longer available for tweaking. Just remember to either tell your victim or to fix it for them or you may be out of a job yourself. opchmod 777 * gives back the permissions. An opls -al will verify this. Now you know what our licensing does to node states as you can set the state of a node to be read and execute only but remove the write to any DOP or POP node and you have a Houdini license while a Houdini FX license will enable the write to all nodes in all networks. Also knowing this, the .hip file truly is a book with a lot of history along with various ways of inspecting who created what node and when, what tool was used to create this node, what dependencies are on this node, is it time dependent, and more, all with a quick inspection. After all this, learning Houdini simply becomes learning each node in turn and practice, practice, practice. Oh and if you haven't figured out by now, many nodes have a very rich history (some older than 30 years now) and can do multiple things, so suck it up, read the node help cards, study the example files and move forward. The more nodes you master, the more you can see potential pathways of nodes and possibilities in your mind, the faster you work, the better you are. The more you do this, the more efficient your choices will become. The learning curve is endless and boundless. All visual. All wysiwyg.
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