Jump to content

Search the Community

Showing results for tags 'particles'.



More search options

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


Forums

  • General
    • Lounge/General chat
    • Education
    • Jobs
    • Marketplace
  • Houdini
    • General Houdini Questions
    • Effects
    • Modeling
    • Animation & Rigging
    • Lighting & Rendering
    • Compositing
    • Games
    • Tools (HDA's etc.)
  • 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 424 results

  1. wave-like information transfer

    I am building a flock using separation, cohesion, and alignment, but I'm modifying the alignment variable. Research showed that you can use a superfluid equation to define the speed of the turn information traveling through the flock, and that helps give the flock that really fluid look. I'm trying to figure out how to control the speed of the information. I need to 1. be able to dynamically change the speed of the information based on the flocks cohesion (when they're more cohesive, the information travels faster) 2. be able to send out "waves" of information every frame, so 24 times a second 3. send out non-disappating waves (I tried the ripple solver, but one of the problems was the dissipation of the magnitude of the wave) I'm thinking CHOPS might be the best bet, but right now I'm just finding a lot of CHOPS information dealing with sound and audio. LMK if anyone knows of a good node that could help me. Right now I'm looking into just hard-coding it in VEX (basically storing the velocity of ALL of the boids at 10 frame intervals), but that will be VERY intensive.
  2. I have a scene with a lot of particles that I am trying to optimize. I've already culled the particles outside of the camera, but I want to get rid of the ones that aren't seen by the camera's rays (the shape is blobby, so I can't just use the z position). What I'm trying to do is take into account the pscale and delete the particles that are hidden behind others. I have a basic working solution in sops via a for each, but it's painfully slow. I want to try and do this with vex. The end result would need to work on millions of particles. The basic steps I thought of are: 1- find direction to cam 2- ray particles to cam (rayline) 3- find neighbors along the rayline 4- use pscale to determine if this intersects with neighbors' pscale 5- if it intersects multiple times, remove the original point I've attached a file for what I used in sops. If anyone has any ideas on how to make it faster or a way to get it working with vex it would mean the world to me. I assume it would be with the intersect() function, but I'm not very familiar with it. Thanks particle_intersect.hip
  3. Delete Vellum Particles with constraints

    Hey Guys. I was wondering if there is a way to delete particles in a Vellum simulations when they have had constraints? The scenario I have setup the particles have constraints, then I remove the constraints based on a condition, and when I try to remove the particle as well it craps out on me. Attached is a simple example file to showcase the issue.DeleteVellumParticlesWithConstraints.hiplc Thanks
  4. particles disappear after colliding

    Hello guys, I'm trying to build a simulation of blood through a vein. The setup is simple, a vein (tunnel) with particles moving through. They collide with the vein and themselves. I then use this sim to copy objects on the particles. The problem is each time a particle collide, it disappears... And I haven't setup the collision response to die... How could I fix this? Thank you... PS: I want to use different models for the blood so that is why there are several objects. Alain bloodflow_sim_debug_001.hiplc
  5. hi, i want to ask that how i create shape(skull) from a smoke(cigarette smoke) ,i try many things but can not make so can anybody help me regarding this
  6. Surface Advection [Houdini.School]

    Hi all, just wanted to let people know https://www.houdini.school is having a 15% off Labor Dale sale. Use LABOR15 at checkout. Ends September 6th, 2021 PDT, so move quick. The sale includes new classes too. I have a brand new live class coming late September as well called Surface Advection. You can enroll and view a teaser video here: Surface Advection
  7. Houdini Artist

    TOYBOX ANIMATION NZ is looking for remote Senior Houdini artists for an abstract/experimental project. Ideally you would be available to start asap. Please send example of your work and details to:play@toybox.co.nz
  8. Flickering Liquid

    Hi there! I have this melting setup with a POP solver, basically scattering some points onto the original mesh and then melting then and meshing back everything again using "particlefluidsurface". So I have been trying to get rid of this flickering on the mesh, I have over 500k points and I also tried increasing the samples and playing with the particle separation in the "particlefluidsurface" I also tried using "vdbfromparticles" but its more or less the same result. I want to know if there is anything I can do to help reduce the flickering? Any help on this is much appreciated Thanks in advance untitled10.mp4
  9. Free video tutorial can be watched at any of these websites: Fendra Fx Vimeo Side Fx Project file can be purchased at Gumroad here: https://gumroad.com/davidtorno?sort=newest
  10. Free video tutorial can be watched at any of these websites: Fendra Fx Vimeo Side Fx Project file can be purchased at Gumroad here: https://gumroad.com/davidtorno?sort=newest
  11. Group particles with maximum age

    Hey everyone! I got a very silly question, it seems simple but i cant figure it out! I have a Flip sim with reseeding "on", I had to turn it on because of the look i was looking for, so particles are constantly dying and generating overtime. I would like to randomly group those particles that doesn't die until the end (basically their age is maximum) and clone sphere on them, I have age attribute from solver but for some reason values are changing uniformly for all the points! I tried making my own "age" attribute using SOP Solver with @age += @Timeinc and attribute transfer but the results wasn't accurate enough because of "attrib transfer" approximation nature. So, I guess my solution is to group all the particles that are present in the last frame based on "id", keep them and delete the rest of them, I guess gotta do it with Vex using arrays and stuff but I'm a noobie in vex! I know it sound confusing but I appreciate if anyone has a solution for this Thank you
  12. (I have posted on the wrong sub forum, reposting here) Hello everyone. I have been using Houdini to Niagara on several projects for now and it works fine. However i would like to loop some of my sims. I do it with a couple of time remap nodes in Houdini. Of course it doesn't work within Niagara. (the sim ends in the middle, exactly where the "end" of the sim is and the second part is not showing up). I tried to alter a few attributes ( age, life ) with no success. I am wondering if there are intrinsic attributes that should be changed in order for this to work? ( I have attached an example ) let me know if I missed something. thanks! looptoNiagara.hiplc
  13. Free video tutorial can be watched at any of these websites: Fendra Fx Vimeo Side Fx Project file can be purchased at Gumroad here: https://gumroad.com/davidtorno?sort=newest
  14. Heightfield particle collision?

    Hi, I'm extremely new to Houdini and I'm trying to create sand winds like in here: My approach is to create particles (sand grains) that spawn on the heightfield, before being blown by a wind simulation or something (or instead of individual grains, just a smoke simulation) What I have so far is a Procedural desert heightfield. I followed a tutorial to set up a smoke simulation that advects to a pyro,, but I'm struggling with setting up collisions and figuring out how to spawn the smoke/sand procedurally on the heightfield. My pyro sim: My heightfield: Any help would be much appreciated! I can elaborate on any part so I can get advice better.
  15. Hello, I'm brand new to Houdini and have been working on a "shockwave" effect and I have just looked in the Render View and there was only black screen. Then I tried to actually render it but it would still only show a black screen. I've attached some images below to show the issues that I'm having. This is my Network inside of a Geometry. This is how it looks inside Scene View. This is how it looks in the Render / Render View. Here's the project file. Please help me out if you can learning shockwave.hip Thank you.
  16. Hello! I've been using Houdini as a TD for about 2 years now and I just recently got my hands on a C4D and X-Particles license. Playing around with X-Particles it has become apparent that Houdini can make something fairly simple (like particle simulations with constraints) very difficult. For these past 2 years I've been trying to get, specifically, thick liquid like particle constraints (not just viscous but stringy) working in Houdini and I've never been able to get results I can be completely happy with. I've been able to achieve "sticky" effects using vellum grains and vdb meshing before as seen here, however, I was always after a different effect using a particle simulation that was NOT attached to a mesh but still behaved in a similar "sticky" fashion when coming in contact with colliders. After trying this over and over again in Houdini and having unsatisfactory results, I've now experimented with X-Particles and I was a slightly frustrated by all of the time I had spent in Houdini and how simple and quick it was to achieve exactly the effect I wanted in X-Particles. In the video below you can see what effect I was after in XP. I was curious if anyone at all has re-created this stringy liquid effect in Houdini with POPs? It seems clear to me that FLIP fluids are not really the answer for small scale simulations where you want a "stringy" surface tension look. I've gotten close with FLIP and vdb meshing in Houdini, but it never looks as natural and real as X-Particles. I've heard that maybe the POP Fluid node may be the answer (here), but I'm curious if anyone has attempted these stringy constraints in a Houdini project! Any Houdini workflow tips for such an effect would be appreciated because the cost of X-Particles and C4D is not something I plan on paying for the rest of my days!
  17. Free video tutorial can be watched at any of these websites: Fendra Fx Vimeo SideFx Project file can be purchased at Gumroad here: https://gumroad.com/davidtorno?sort=newest
  18. Fluid Along Surface

    Hi Guys, I'm new to Houdini so please, bear with me:) So, what I want to achieve is following: I want to have fluids (or particles, through POP Fluid), that would go up against the gravity (antigravity) along the collision geometry, upwards, along the vectors that are parallel to the surface of geometry. The effect should look like a paint going down on a surface, and covering it, but the direction is reverse, so it goes upwards. The collision geometry is simple, like a sword, thats it. I tried to do it with flip tank, with attraction force, but somehow I couldn't not get the result I was hoping for. Can you please show me the direction I have to follow or an advice I can follow to achieve this result? Is it better to do it through Flip or through particles? Thank you in advance. Cheers, David
  19. Hello everyone, I am a new Houdini Indie user, so i might have missed the obvious. I am exporting a particles explosion from Houdini to Unreal. it works great except for the trail node. It does export the datas ( file is much heavier with trail node) but the trail node is duplicating the particles id ( and probably all the other attributes). Once I import a cache in Niagara, I only see the particles from the POP and not the one from the trail. I tried randomizing the id attribute on a static particle system, and the trails points do appear properly. ( on an animated one it juste pops a random particle every frame). I was looking for a way to either, give the trails points an id or create a trail directly within my popnet. For the second option i basically want to pop a particles every frame with a 1frame life from each points of the simulation... but I cant find how to do that. Do you have any leads to what route to take? thank you!
  20. I'm sure there is a simple answer for this, but it's got me scratching my head... I'm trying to use the @hittime attribute in order to do some stuff with my @pscale, but it never stops growing even after the particles are stopped by the pop collision detect behavior. The @hittotal attribute does the same thing, like they are all vibrating on the surface or something even though they are not moving. I've attached a simple scene. pop_hittime_1.hip
  21. Alrighy, I have a big wedge of stupid in my head that is keeping me from doing this. I have particles emitting into a container (a super-simplified version is attached). I would like to get it where instead of the usual bounce/slide off a wall, the particles slow down and gradually move/are pushed away from the containing walls. I'm assuming this would be done using SDF/volume sample/volume gradient and a POP wrangle modifying the velocity based on the sampled values, but I just can't get it to work. I've seen lots of tutorials on using this approach to get particles to stay NEAR a surface, but my brain isn't adapting that to a nudge-away-from-a-surface instead of a nudge-towards. What am I doing wrong? The POP wrangle code-in-progress (the collider is input 2, the VDB is input 3): float samp = volumesample(2, 0, @P); vector grad = volumegradient(2, 0, @P); @v *= -grad; SOMETHING is happening, just not what I want. (And ideally I could have a second SDF inside the container pushing out, thus gently keeping the particles within a certain radius of the container wall, not going to the center.) Thanks for any help! example.hiplc
  22. fun and play with particles

    having some fun with particles.... birth of a massive star. for my little #astrophysics exploration, i’ve created a star simulation using openCL in houdini. its based on nbody #physics model, only driven by #gravity. using #nvidia #quadro rtx 5000 #arnoldrender. the colours are not quite right, I am trying to integrate kelvin colour temperature. the current colour is based on density and speed. In this simulation, I assumed 48% amount of negative gravity to fill the mystery of dark matter. I used 1 million nbodies for the simulation. for the steps, I am planning to add finer particle streams to get more details. fast particle rendering with path tracer is hard !
  23. This is my first post in the forum, so first things first: Hello everyone!! Down to business: I'm trying to create a custom 3d vector field from a set of imported lines so I can drop some particle tracers on it. I managed to convert the imported lines to vectors using the orient along curve node, and I also created some voxels through bound>volume (ideally one for each of my imported lines, although I'm not sure I succeded). Now, what I want to do, is to link each one of my custom vectors to it's correspondent voxel, so that when a particle is inside that voxel is affected only by that particular vector. This is where I get lost, I don't know how to link my vectors to my voxels... I tried importing my "vec" point attribute inside my volumevop but for the life of me I can't seem to figure it out. I come from Rhino+Grasshopper, so I thought I'd be a bit familiar with the node workflow and all but... wow... Switching to Houdini feels more like stepping off a meek pony and jumping right on top of an untamed pissed off stallion. I'm attaching my files. Any help taming this beast will be much appreciated (Probeta_02_vF_S.igs is the file containing the custom lines) Custom_vField.zip
  24. Fluids - help!

    Hi team! I have followed a good tutorial on Youtube as I was having issues with keeping fluid in a container, this tutorial also shows how to do bubbles in the water ( Tutorial here ) When the bubbles go through the water there is a loss of fluid and I have been playing around a lot trying to figure out how to prevent the loss, when the collision objects aren't connected there is no loss in the amount of fluid but when I connect the Collison object there is a loss of fluid and I cant figure out how to stop that. I was wondering if anyone else happened to know? Its just bothering me and I wanted to know the answer. Cheers! Hottub.hipnc
  25. Using Engine I have been able to import a particle cache into Maya just fine. Scale and color came through and were easily applied in Arnold. However, I need to recache the particles as a Maya nParticle cache to hand it off to someone else not using Houdini Engine. I can get it to cache the general position/lifespan, but it doesn't appear that any color/scale(radiusPP)/alpha(/transparency) information is in the re-cache. How can I make sure those attributes make it through to the nParticles (re)cache? Thanks for any help!
×