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


  • 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 210 results

  1. I want to spawn some particles (rendered as sprites) and have their entire quad drawn every time -- even if it the quad is intersecting with other scene geometry! Is this possible? I have done this in OpenGL where I just disable depth testing before I draw my particle system but I couldn't find any option like that in either the POP nodes or the shaders. One terrible option would be to render every frame twice, once with the scene geometry disabled and one with the particles disabled and then composite them on top of each other... but that can't be the correct answer. I want to do this because I am trying to recreate the kirakira filter on iOS which overlays the image with jumbo starburst sprites to simulate a combination of glints and diffraction spikes hitting a lens. intersecting_sprites
  2. Saliva FX

    Good evening my fellow Houdini magicians. I have been trying the last couple of nights to create a Saliva Fx for a dragon roar but my brain is completely drawing a blank... So I figured I would try my luck here and see if someone is up for the challenge. any amount of help is appreciated to get me started. I have tested a few things, but I was not happy at all with any of it, so I am leaving a clean canvas here and hoping someone has a good approach to this that can get me going. in my head the saliva would be sticking to the teeth and then slowly get pealed off as the dragon roars, HOWEVER I am not married to a certain look of the FX, I just want to learn how to do a cool saliva FX. I have attached a clean scene file to start from and also the .bgeo sequence in case you cannot see the geometry in the scene from the locked node. Thank you in advance for all your help. Cheers. dragon_head.hiplc Dragon_head.rar
  3. LearnSquared Houdini Particles

    We just released a 4-part particle series I did for LearnSquared: https://www.learnsquared.com/courses/houdini-particles We cover everything from building our own particle solver from scratch, using the built-in Houdini particle POPS, showing how to choreograph and art-direct particle motion, and working through various rendering and instancing strategies.
  4. Hey magicians, I'm learning about velocities on particles, I made a shape that drives the velocity, but the particles are going diagonal instead of straight (the actual shape animation is just a vertical movement). I can't figure out whats driving this, I don't have any forces, any help will be great. Hip attached Thanks! particles.hip
  5. Hello! I'm having a bit of dilemma here... Currently I have a setup in which I'm emitting particles from selected points on my mesh that drive the pyro sim. I'm using the source from points option to do this. It works but I'm lacking control of the velocity. Currently, I'm working on a group of points via the bindGroup option on the attribvop and altering the normal inside the vop. Nevertheless, is this a good way to do this or is there a better method to have particles emit from the gills to drive the pyro sim. Really could use some help on this... thanx!
  6. Particles along surface

    Greetings to the best forum on the web I am struggling a little with wrapping my head around the xyzdist() and primuv() functions in vex. I have attached a scene file that holds a dopnet with some points created on frame 1. I would like those points to stick to the geometry coming into the second input on the dopnet. any suggestions to how this could be done is appreciated. I am in particular interested in the usage of the xyzdist() and primuv() solution, however other methods is also encouraged! should there be some people that wanted to "show off" a little vop magic that is cool too. looking to learn so hit me with everything you got. All in all a simple task but good fun. Thanks for playing Cheers particles_on surface.hiplc
  7. Hi Everyone, I am still new to houdini and I frequently run into the following problem. WhenI use VDB volume for collisions in houdini Particle or Flip sim, particles collide with the bound of VDB volume instead of actual VDB shape. It kind of creates a boundary around VDB and uses that boundary for collision. Its visible in the viewport in orange color (yellow color in the provided SS as d object was selected when took SS). I often get this issue and I dont know what I am doing wrong and how to solve it. Even If I use shelf tool the problem still persists. If anyone of you have ran into this problem then please let me know how u solved it. thank you for your time. Cheers!!!

    Hello, I AM DYSLEXIC - a very nice student project I worked on back in 2015 just got published, I did FX for it, all in Houdini, then handed over caches to lighting and rendering guys (rendered in Mental Ray in Maya). I really like visual style and it was really interesting to do some effects for this style of animation. Enjoy Short breakdown: 00:48 - paper (cloth) sim, a proxy collision geo of hero character was animated and used for interactions 03:22 - RBD simulation advected by hand-drawn guide curves and underlying FLIP simulation, some VDB meshes for hill filling, procedurally generated pages between books with fake dynamics (even though they got totally lost in the renders)
  9. Add custom force to foam particles

    Hi all, Anybody know how to add custom force to foam? I try use popvop but it don't work. I check witewater solver, its looks like force always 0 when particles is foam. Thanks!
  10. Hi Guys, I want to scatter some points on a growing and deforming vdb mesh. These points shouldn't jitter on the surface and look like they are moving along with the surface. I have attached a basic file similar to my actual setup. Basically, I am going to render these particles as bubbles on top of the mesh and I want it to be quite dense. I haven't been able to figure this out and couldn't find much help online. It would be great if you guys can check it out and help with a response. Thanks vdb mesh vdbscatter_v01.hipnc
  11. Loop Particles for Geo Instances

    Hi everyone Wonder in knowing, I am trying to get a kind of loop particles systems, means that when they collide with an object, will recover back their original position and re-simulate creating a loop. Main constraint here is that ptnum must to be constant, cannot die. After this it would allow to set different conditions as reboot when leaves frustrum or after a certain initial age, etc. My only issue is that I arrive at update (in the wrong way for being honest) the velocities to re-do the sim cycle, just that goes in the worng direction, exist a way to make them restart with their initial velocities, attached a HIP file of example. Thanks LoopParticlesTEST.hip
  12. Sparks direction

    I have sparks emitting from my object based on the velocity of the object hitting it. The problem is my sparks are traveling too much in the Y direction and need to spread out more (examples, references, .hip and renders attached) Instead of manually animating the sparks in the direction I need, any ideas on how I could keep this procedural workflow while getting the sparks to travel in the direction I need? Thanks sparksContact_v004.mov sparksContact_v004.hipnc
  13. Hello Pals, Hope you all are having a great year so far. I am trying to do a shot with particles which needs slow motion on a certain camera moment. Basically, I just want to slow down the motion of my particles for few frames. I dont want to mess with the velocity etc as I really like the motion of my sim. I looked into time-shift, time-warp etc. But they always feel like a cheat and not much of a high quality solution. There is a "Scale Time" option on the POP net. But for some odd reason its locked and we cant key-frame it at all. That would have been the best solution, where we can just lower the timescale for bunch of frames and then resume it in normal speed. Can anyone just give me a brief why Sidefx would want to make this such a big deal and lock it on POP nets? Thank-you and have a great day! HD
  14. Smoke & Mirrors ... a NYC post house needs an artist capable of create a macro demo with a biomedical feel. Should be comfortable with Flip/SPH Fluid, Particles, Pyro as well as procedural animation and deformations. This project is self contained so working remotely is a possibility. If you are interested you may contact me directly here for more info using PM here. Thanks
  15. Particle PROBS

    So ive been working on a particle disintegration for a couple days now and I just ran into a huge issue! My teacher said it looks like its produces sprite cards instead of particles! anyone have a way to make it work as needed? need simple particles instead of sprite cards! PLEASE HELP!!!
  16. Retime slow motion points

    Hello all, I have a sand set up based on points being advected by vdb vel. The results come out nice enough but the motion is too fast. I need the speed sim/solver speed to remain the same though to retain the kind of details I'm getting so I can't just multiply the fps down in the solver to cheap a slow-mo effect. What I'm looking for is to simply retime the points post-cache and make my cache slow-mo, which actually works using a timewarp (I just stretched the output range an extra few hundred frames) -- The slo mo effect is achieved but there is obvious stepping in between frames where the cache will freeze and play ever other frame (due to the stretching) To avoid this kind of stepping I tried using a timeblendql, which seems to have almost worked but because my points are dying and being deleted based on age, the timewarp breaks. Timewarpql has a neat feature where you can use the v of the point to blend between subframes, but since I'm inheriting my point v from the vdb vel its not as accurate is if you were using a trail sop, and again the trail sop breaks in my scenario because of the points being deleted perhaps based on age.. I can smooth the points together in post with nuke using a frameblend and you don't see the stepping... But i'm sure there is a proper and procedural way to interpolate between the substep frames of the point between A + B... just not sure how to go about this and I am having trouble finding a reference on the net. It would also be nice to have this setup on hands in the future. Thanks for all your time!
  17. Hello, I was wondering if anyone had any suggestions as to why my flip fluid sim seems to "compress" as my container moves. Any help would be appreciated. Thanks!
  18. I am trying to do a sort of Sci-Fi explosion, still deciding on the story behind it, but I know the look I am going for. I want to have an energy core going critical with energy masses spinning around it as if following magnetic field lines. I finally got my field lines working right and got them into a vel field, but now I can't figure out how to cause it to animate the particles. I plan to generally control the animation from this velocity field, so it is really important that I actually get it working. Any suggestions? I have attached the R&D file I am working with so you can see where I am with all of it. particleTest1.hip
  19. Birth particles on a shadow

    Hi im having trouble to determine a way to birth particles (constant, 1 frame alive) only in the shadow of an illuminated object, the light moves in every frame.. any ideas?
  20. Hey all: I have a particle simulation with particles shooting outward from the origin. I am using the particle replicate to emit particles from particles. Here is the problem, I want the particles close together at the top but further away toward the bottom like the photos shown below. My Idea was to do a point jitter based of the age of the particle, so that new particles will have no jitter while old particles will have jitter. Would it be possible to accomplish that using vex in an attribute wrangle? Or could it been done in a point VOP with a slider to adjust jitter by age? Or is there a better way to have the older particles move out further outward? than using point jitter? explosion001.hipnc
  21. I'm currently following along with Rohan Dalvi's Motion Graphics tutorial, and I've run into two issues with the particles from the outer ring that I thought would have simple solutions, but so far have completely stumped me. The first thing I've found is that each point would spawn two particles, resulting in two lines very close together, and I want to get only one particle/line for each spawn. I've figured out the reason for this happen is that in my POP network I do two separate replicates, each on a different particle stream/group (so that I can have differing life lengths), and the replicate POP passes through the original particles (even those no being replicated) so after merging the replicates back together, I end up with two separate sets of the original spawner particles. Now the solution I came up with was to remove the points I didn't want to replicate, do the replicate for each group, then merge them back together (exactly like I would if I had this issue in SOPs). Problem is though that didn't work at all. I tried both Kill POPs and POP Wrangles, and a few different setups but nothing worked. I've included some notes with the scene file to give better explanations. Secondly, when the spawner particle collides with the tube, the replicator keeps replicating it, so we end up with a bunch of points stacked on top of each other, which I don't want. My idea to fix was to have a node placed straight after the replicate that removes any particles in the "hitparticle" group from the "stream_General_Spawner" group. That way, on the next frame, all the collided particles won't be replicate again. But this didn't entirely work either. "Combine Groups" on the Group POP almost did the trick, but in addition to removing the particles from the spawner group, it also removed them from the hitparticle group, which I don't want because I have a wrangle that does stuff with that group. Does anyone know why these issues exist? I'm guess that I'm missing some sort of foundational knowledge on how POPs work? Any recommendations for tutorials or articles to go along with the documentation to help with this? POPs_problem.hipnc
  22. hey guys so this one is thumping my head i have a popnet with some grains... its working well. now i want to simply cache out this simulation to disk, then bring it to another hou file. But what is the best way to go about that? I'm just lost here. i can cache it out a .bgeo sequence and then fetch it in with file read node into a blank hou scene but the grains have lost their spherical look and the ramp colour too ? I cant for the life of me suss out how to plug this into a new popnet scene anyone with any advice much appreciated losing my head here ant
  23. POPsolver not working

    I'm trying to source particle emitters from geometry that i created in a scene. Unfortunately, there seems to be an issue with the popsolver node, it's saying that: 'Connection 2 input is the wrong type' I'm trying to create a whisp effect, following some tutorials but already stuck and not able to continue. Please help! WhispIssue.hipnc
  24. Hello, problem how can I use the imported vertex color of cached particles in Houdini with a cloner in Cinema 4D? Story I simulated and cached simple particles in Houdini and imported in Cinema4D by alembic format. They have colors according some rules created in Houdini, in the end, it's just plain Cd. If I select particle when importing, I see no particles in viewport, so I switched to polygons. When I use a cloner to clone a sphere for every vertex, I expect the sphere to have the same color of vertex, like you normally have with a copy node, instead the sphere has no color if not the one of the shader. I know, I already asked in an other forum about this problem more about Cinema 4D than Houdini, with no success, it seems to me it's not straightforward like in Houdini, of course, with all the respect to Cinema 4D, fantastic program, and its community, but I was wondering if someone had the same problem and found a solution. Thank you in advance.
  25. Hey all I am working on a shot that needs ink to morph into a Heart then into a Ship. I have the base of the effect , although my last morph is a little quick,need to figure out how to slow the ship morph down a bit. But my main issue is my particle advection isn't working correctly. The particles are inheriting velocities but they are not following the smoke sim correctly. They don't form the desired shape even though the pyro sim is. I have a scene attached if anyone could help it would be appreciated. Kraken_MAIN_Ink_Effect_09.hip Ship_Mod_v01.obj Heart_Mod_v01.obj