Welcome to od|forum

Register now to gain access to all of our features. Once registered and logged in, you will be able to contribute to this site by submitting your own content or replying to existing content. You'll be able to customize your profile, receive reputation points as a reward for submitting content, while also communicating with other members via your own private inbox, plus much more! This message will be removed once you have signed in.

Search the Community: Showing results for tags 'bullet'.

More search options

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


  • General
    • Lounge/General chat
    • Education
    • Jobs
  • Houdini
    • General Houdini Questions
    • Effects
    • Modeling
    • Animation & Rigging
    • Lighting & Rendering
    • Compositing
    • Games
  • Coders Corner
    • HDK : Houdini Development Kit
    • Scripting
    • Shaders
  • Art and Challenges
    • Finished Work
    • Work in Progress
    • VFX Challenge
    • Effects Challenge Archive
  • Systems and Other Applications
    • Other 3d Packages
    • Operating Systems
    • Hardware
    • Pipeline
  • od|force
    • Feedback, Suggestions, Bugs

Found 95 results

  1. I'm gradually trying to learn various of Houdini's solvers (primarily cloth, pyro, and bullet for now) and I'm slowly getting to grips with how they work individually. What I'm struggling to understand, and also struggling to find good learning resources for, are the ways to create interaction between multiple solvers. I'm interested in setups for one-way interaction (eg. pyro affected by bullet/rbd sims) but even more keen to understand two-way (or more) interactions. For example, how to have cloth and bullet (and perhaps pyro as well) all working mutually in a dynamic simulation, all affecting each other. Can someone point me in the right direction towards learning how to combine different solvers together? Are there generic ways for doing this (in other words combining cloth and bullet would involve the same understanding/setup as combining pyro and cloth), or does every solver/combination have its own idiosyncrasies when trying to combine? I found this video about combining pop and bullet solvers: https://www.sidefx.com/tutorials/combining-solvers-with-a-multi-solver/ I assume a good understanding of the multisolver is key here. But the multisolver doesn't accept the cloth solver as an input, so it seems like there must be more to it than that... Any help much appreciated!
  2. i have managed to create a network of masked gravity force to drive the RBD packed objects but I'm a little confused about how to proceed further. i need to control the moving pieces of geometry more effectively with further forces as well as create debris from the cracks or where it fractures. any direct help (i have attached an example file) or pointing me towards resources where i can learn further would be cordially appreciated. thank you and best regards fracture.avi fracturingGeoMaskingForce.hipnc
  3. Hey guys, working on a destruction peice and wanting to take the velocity from my charachter and put it into my bullet sim - So decided to try and use a sop geometry node to bring in the calculated velocity (from a trail and fluid source) - which is working perfect. But my sop force doesnt update each frame, its static - ive tried changing the expression from $T to $F and other things, not sure if its a limitation or if im doing something wrong? i will attatch a file but will be missing the geo but atleast you guys can see the setup Any help would be great! Thanks Destruction_v3_t2.hip
  4. bullet

    Hi guys , Based on the tutorial Applied Houdini - Rigids II Structure Destruction I'm try same effect , But i have trouble is instance pack , i m use same techniques in this scenes . But i don't know why matrix replace does not work . Hope your help .Thx every body. Please find attached for details
  5. Hi everyone, I made this setup to mix constraints between conetwist and glue, depending on angle value, i set the constraint_name in a sop solver plugged in the constraint network node, it works quite well but the resulting object is floating in the space... is anobody here can check my file and tell me what's going on!!!? apparently its not a subsanple or CFM, ERP issue ( i checked all this parameters and, nothing...) thx by advance, Best regards H TEST_PACKED_CONST_METAL_V002.hip
  6. Hey guys, Im creating some procedural Sawdust using the copy sop onto a point selection - i want to sim the objects then dropping onto the terrain for placement, but so far have had no success - tried changing collision modes in Bullet but think the main issue is its all connected as such? (have tried convex hull and per connected set of primitves with no luck etc) and cant think of a way using the skills i have to select every peice of geo individually and then make dynamic quickly without doing it manually (which with thousands of peices of geo is not a good idea) Any help or ideas would be great Thanks Chris
  7. Hey guys, Im creating some procedural Sawdust using the copy sop onto a point selection - i want to sim the objects then dropping onto the terrain for placement, but so far have had no success - tried changing collision modes in Bullet but think the main issue is its all connected as such? and cant think of a way using the skills i have to select every peice of geo individually and then make dynamic quickly without doing it manually (which with thousands of peices of geo is not a good idea) Any help or ideas would be great Thanks Chris
  8. Hi, I am an experienced Software Engineer with a good eye for Visual Effects. I have over more than 10 years of experience in developing advanced software systems for simulation and animation companies. In addition, I've invested that last 5 years exploring and educating myself all about Visual Effects. Below is my demo reel. Please check https://www.linkedin.com/in/khaledabdelhay for more details on my technical/artistic skillset.
  9. Hello there, For my current project, I have a subset of randomly oriented geometry (mostly box or capsule like shapes) in one .obj I would like to orient all of them along their main axis. I remembered Bullet had a Autofit feature, that would fit specific geometry (Sphere, Box, Capsule, etc) to your geo. I tried looking up the source code for this, but I don't think the effort would be worth trying to understand the whole code (I'm a very beginner coder unfortunately), and secondly I think the bullet solver inside houdini does a pretty fast job as is. My approach is now to import all the objects to bullet, calculate the AutoFit there, and then get the orientation for each object. But how exactly can I access the Bullet Collision Orientation? In my subdata it shows no orientation (obviously, because my parent node is not rotated or transformed), and in the bullet data tab i cant seem to find any orientation. Is this even possible? Or can someone here share and explain the AutoFit code inside Bullet? (Just Kidding ;)) Best Regards Bajt *edit : I just remembered one more question, even though it's not directly related to this one: Is there a way to calculate the best fitting primitive for a shape? I read the paper https://www.cs.drexel.edu/~david/Classes/Papers/MeshlessDeformations_SIG05.pdf , but when i understand this correctly it only works if point numbers and number of point match in both point clouds. Maybe its possible with bullets autofit algorithm?
  10. Hello I have scattered points, a lot of them and I copy some simple objects, which represents roughly my Hires Geo. Problem is, that whole system is procedural, so I never know if Ill be simulating 20k or 50k objects. Ofcourse more objects, more penetration on first frame. So I have an idea, to do a small sim, where on couple of frames play new bullet sim and all penetrating objects will move until theres no penetration (say time shift 10-20f). Then I`ll start my main sim without penetration (a lot of different constraints, some groups of active objects.....) But problem is, that bullet do nothing even there`s a lot of penetration. I cant find any parameter in bullet solver, rbd packet prim, which will help me. Ofcourse Ill be happy to hold main shape as close to original as possible. There is simple scene. Thanks a lot. bullet_penetration.hip
  11. the "collisionignore" point attribute works when it is ignoring static RBDs, however it doesn't seem to work when ignoring active RBDs.. is this a bug?
  12. Hi guys, Wanna share with you my recent rbd tests. In my opinion, such workflow is pretty similar to FEM (DMM) based solutions, but gives a couple of advantages. For instance, we can add details only where we need it. I hope you understand, that I can't share hip file, but I'll try to answer to any questions. cheers
  13. Hi, I have a question about setting up collisions on a static object. My goal is to have a character walking through snow. I have a grain simulation and then an alembic of a character walking. I have my grain simulation setup, now I need to make my character a static object so it collides with the grain pop simulation. I then made my character walking alembic a static object. Now here is my question: I need to edit the collision boundary of my character walking, but how do I know which solver is being used? Bullet, ODE, or RBD? To sum it up, I have a static object being used as a collision for a pop simulation. How do I know what simulation engine is being used to calculate collisions? Bullet, ODE, or RBD? Thanks in advance
  14. Hello, I'm playing with bullet dynamics in Houdini. But I'm having quite often one problem - strange motion in e.g. small shards on ground plane. They don't stop moving even after few seconds after they fell on the floor. They are not changing position but just slightly rotating. This motion seems to go on and on... According to docs Linear/Angular Treshold parameter in RBD Packed Object should fix it, but it doesn't seem to have any effect. Have you experienced this type of error and if - have you solved it? Thanks
  15. Hey, im not sure if this has been asked before but im trying to do the maya ---->houdini---->maya workflow. But im stuck at one point. So when i export models, specially stuffs like wooden tiles or brick walls as abc or OBJ to houdini. Houdini reads it as a single file. So that stops me from using voronoi on per object level as it applies it to the whole models as one single object. Like for example i want to fracture the whole brick wall but i want to do it per brick level not as a whole wall. If this has been asked im sorry, but really need to get this figured out for a project. Thanks alot
  16. Hi guys, I just want to ask one quick question. I am using bullet solver and want to count hit value of pieces with collision geomectory. I tried pop collision detect also but its not working on rbd. thanks
  17. I'm trying to figure out the best way to transform packed RBD primitives. I'm doing this by modifying the packed primitive intrinsic 'transform'. The issue I'm wondering about, is that the collision hulls that bullet is creating (packed rbd object > bullet data > show guide geometry) change every frame, which seems weird. I want to create the collision hulls on the first frame, and then transform those shapes. I've tried 2 different ways in the attached file. One I set the 'initial object type' to 'create static objects', and then I transform them inside the sim using a Geo VOP DOP. The other way, I'm setting 'initial object type' to 'create animated static objects' and feeding in the transformed pieces straight into the sim. Both produce the same result, and the collision hull seems to get updated each frame. Is there a way to make sure the collision hulls not update each frame, but still give them rigid transforms? Thanks! xform_packedRBD.hipnc
  18. Hi, Im trying to let a fluid drive my rbd/bullet object but it just doesnt work. Never did this before. Does anyone have a quick example? tried multisolver, merge Left input to advect right, ... Just a simple smoke shelf and object would be enough as a example. Like particle advect, but with geometry. THNX alot
  19. Hi guys, I want to make sim with already simmed geometry. In TP in Max it so simple. Just use cached geo like collision, add constraints and sim. But in houdini i have trouble with it. What workflow in this case? I try use cached geo like rbdstatic obj, but when start sim it intersecting with active geo and looks not good.
  20. Hello. I just recently graduated from VanArts which is based here in Vancouver. I have completed my demo reel in FX which is to say primarily using Houdini 15.5. I hope you all enjoy watching it as much as I enjoyed creating it. I am attaching the link below. Please let me know of any suggestions, criticisms all is welcome. Thank you. FX DEMO REEL 2016
  21. Hello I need to deactivate a passive collider at some point in my sim, and I can't figure out a simple way to deactivate it. I've tried groups, affectors, 'active value'. It's probably a simple fix, but the only 'hack' that I've found is to use a merge under my static object (merge with a null) and keyframe its activation between 1 and 0 Thanks in advance Bernie
  22. Hi, I'm experiementing a bit with bullet and fracturing and did some simple tests. If I know it correctly then the simulation base unit in Houdini is meter, so 1 unit (e.g. a basic polybox) is 1 meter large. If I now try to simulate real geometry like a bottle or a cup of tea, then my geometry is maybe only 0.3 units large for a bottle. These are my results: First, the real size, 0.3 units large, no substeps, convex collision geo: bullet_01_convex.mov As we can see, the collisions are quite inaccurate and the simulation is jittering a lot. That's simply because the collsion geo is inaccurate. So I switched to concave and tried again. bullet_01.mov That's more accurate but still jittering a lot. So I switched back to convex and modified the collision padding to get a better representation. bullet_01_convex_collpad.mov Collision is better, but we still have a lot of movement in the geometry. So maybe it helps to increase substeps? I increased them to 10 on the dop node. bullet_01_convex_collpad_sub.mov As you can see that was not such a good idea, the parts are jumping around like crazy. So Now I started with an increased scaling of the geometry and increasing the gravity at the same time twice, once with convex once with concave. bullet_02_concave.mov bullet_02_convex.mov Now the convex sim starts to look better. Just for testing, I increased the scaling up to 3 and did it again: bullet_03_concave.mov bullet_03_convex.mov Looks very much better. Now I tried with my real geometry: bullet_04_concave.mov still some jittering, and not enough bounce, so I increased the bounce. bullet_04_convex_bounce.mov And a bit more bouncing. bullet_04_convex_bounceHi.mov Now it looks more the way I want it. So my final conclusion is: Even if it may be physically correct to simulate a 30 cm bottle in real size, the only way to make it work as expected is to scale it up several times, simulate and scale it back down. Is this correct and can anyone confirm this? Maybe I'm completly wrong and simply missed some of the many settings in Houdini so I attached my scene. Here the uniform scaling of "transform6" node in the "alembic" network is connected to gravity to make it automatically higher if the geometry grows and bounce of groudplane and geo is higher than default. Scene file: bottle.zip bullet_01_convex_hull.mov
  23. Hey guys. I'm trying to figure out a destruction setup for things like fences, wooden frames, plywood walls (that thin stuff thats really easy to put a hole in accidentally) etc. The part I'm stuck on at the moment is how to mimic things that are nailed together. Specifically, how to set it up so that when the fence/frame/whatever is hit by something, it doesn't just break apart, but instead just becomes a slight bit loosened, causing it to wobble a bit and fall over slightly. I realize that explanation probably makes little to no sense, so I've included two reference images. One depicts the effect that would happen for an entire fence, the other is for a single beam. I've got an example scene that uses the Cone Twist Constraint. It it gets me part way there, but is obviously way to static, and just stops suddenly. What I would like would be some subtle wobbling, as well as the beam the rotate down abit (to mimic the photo with the horse). I had the idea of using a Glue constraint with a bit of stretch. Problem is, I have no idea how to get a glue constraint to stretch (or if its even possible) and I couldn't find anything on Google about it either . Is anyone able to point me in the right direction for figuring this out? I'm still struggling to understand constraints so any guidance would be extremely helpful Nailed_Wood.hipnc
  24. BulletSOP is implementation of Bullet library (bulletphysics.org) inside SideFx Houdini (sidefx.com). It's a plugin for creating incredibly large rigid body simulations on average PC. The Tool is very powerful, flexible and speed is very impressive as well as memory footprint. The plugin is free and without limits! So you can create truly stunning massive simulations. BulletSOP is compiled for Houdini production builds. It includes many example scenes (beginner -> professional) which are probably the best learning resources. Main features: - Bullet RBD Solver - Support for multiple Broadphases, Constraints Solvers - Loading data from previous frame - Geometry decomposition (Tetrahedra, Voxels) - Static/Animation body - Convex Hull - Compound Hull - Deform static Hull - Primitive Hulls - Constraints (auto-generating, spring, 6DoF) - Collisions Groups - Object Forces - Point Radius Forces - Delete Duplicity data - Instancing - Emitting system - Includes many example scenes for studying - Support for Windows(64bit), Linux(64bit) and OSX(64bit) Links: Houdini: www.sidefx.com LinkedIn: www.linkedin....Houdini-4796605 More author's videos: vimeo.com/user3251535 Create freely, simulate quickly and enjoy fully! Best wishes, Milan Suk Download BulletSOP v2.0.15 for Windows, Linux: http://bit.do/BulletSOP_v2_0_15
  25. Hello, I'm doing a simulation where a car drives through a brick wall. The scene will eventually be imported via alembic into C4D for texturing and rendering so here is where I'm getting stuck: I imported the car as an obj, cleaned it, converted it to polysoup, made a low res proxy (using the ray sop) for simulation, and then after I get the sim the way I want I export the point data of the sim and then use transform pieces and connect the high resolution car. However, I'm not sure how to export the car with selection tags for texturing individual parts of the geo in C4D. I'm using alembic to export from Houdini to C4D. It seems like once I convert the car to regular polygon mesh, all the individual pieces of the car fall apart in the sim. I would use an HDA and the C4D Houdini Engine but we are on R16 at work and will not have R17 available to us for this project. Is there a way to save out texture tags in the polygon soup so that when I save the alembic file they are baked in? Any ideas are welcome! sim_example_js_v01.hipnc