Jump to content

Search the Community

Showing results for tags 'pop'.



More search options

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


Forums

  • 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 85 results

  1. Granular Sheet - Moving Pin Constraints

    Hey everyone, after unsuccessfully scouring the web and the two big Houdini forums I finally brought myself to asking directly. I'm currently trying to animate a sheet of cloth using a granular sheet since the FEM approach is just excruciatingly slow. I've found three methods for pinning parts of the granular sheet in position (@stuck, @mass = 0, @targetP) but I wasn't able to find a use either of these methods for an animated pin constraint. I'm obviously still not really proficient in Houdini since this problem has me completely stumped. So if any of you lovely people would point me in the right direction, I'd be immensely grateful. Thanks in advance! *edit: After searching some more, I came across this thread: While the file attached to the thread works when I play it, when I try to copy that setup into my scene, it just refuses to work, even though the @targetP gets updated. Obviously, I'm doing something wrong but even comparing the node settings side by side I can't for the life of me figure out what that something is. *edit #2: Okay, I finally figured it out. I didn't realize that the sop solver node is empty by default and you have to create the sop structure to update every frame by yourself. Now that I've figured that out it is perfectly reasonable, I just didn't think of that for quite some time. dia3_dmo_001_010_cgfx_setup_v003_pj_stripped.hip
  2. 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
  3. Hi Odforce. I have POPs moving past a point and I want the stream to inherit and keep the points normal after passing. I thought this would be a straight forward pcopen() case, but I cant get it to keep the normal. It's only there for as long as it is within the search radius. I've tried a few different things in vex. wrapping it in an If statement instead of while, but to no avail. Edit: I should maybe mention that I'm in SOP right after importing from a DOP. Tried to make it work in POP wrangle but had no luck there either. Thanks, Bastian
  4. Hey magicians, Been fighting with this pile setup for a couple of days, I need to make a candy pile, I'm using grains but when I replace the geo there are some artifacts like the geo is inside the particle and leaves weird holes, anyone knows how this can be fixed? It need to be the more realistic way possible @f1480187 would love to hear your thoughts sensei Thanks pile3.hip
  5. RDB driven by POP network

    Hello! Firstly, I'm very new to Houdini (coming from Maya), so I apologize if this has been posted before; when looking for a solution I may have just not searched the correct terms. At 49:00 in the below video, Jeff Wagner demonstrates an RBD solver that is 'driven' or on some level involves a POP network. I want to achieve a similar effect. I currently have a shattered object (using another tutorial to create jagged voronoi). Additionally, I'd like to scatter points along the inside point group (from shatter) to create wires, Entagma recently released a tutorial that I can probably use. Getting curves that are affected by gravity would be a perk, but it might be beyond ability trying to make them dynamic constraints to the shattered pieces, etc. If I don't do this however, I might have an issue with them clipping into the geo. Thoughts on how to make them collide-able at least would be appreciated. Would love anything to point me in the right direction. Thanks!
  6. 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
  7. Hi, I'm trying to replicate the way you can set color for a particle's "initial state" in a Maya particle system. I've looked through docs, tuts, etc, and have not been able to get this to work: Here's what I got so far: ---------------------------- I've scattered points over some terrain Geo, used a point Vop to create noise based color for the Cd attribute on the points, then used the points as the initial geometry in the popObject. The idea is to have textured "dust" blow over the Geo (I'm driving the pop animation with a Pyro sim). The animation works well, but I can't figure out how to transfer the Cd attribute of the scattered points to the particles. I played with creating the color with a PopVop in the Dop network, but the color is assigned by position so the particles animate but the color does not. I've attached my test scene. I'd appreciate any clues; thanks in advance bcs_partDustTest_v01.zip
  8. Copy Debris Mesh to Pop

    Hey guys, Does anyone knows how can I copy these debris into the Pop Simulation points? (Scene file is attached) copy.fragments.to.particles.v1a.hiplc
  9. Basically, I'm creating a scatter points in a surface and I plug a POP Network, so I want that the Pop Network import those scatter points as particles, but I don't know how to do that. Can some help me to do it?. So I want to put the scatter points and use it as particles.
  10. Hi.I want to emitt particles from a boiling geometry(geo with spheres, at a random lifetime). But i need to activate emitting just as my “boiling sphere” is at the end of its lifetime. Im using two popnets, but no sure if thats nessesary.I cant to it with keyframes expressions it seems, because my boubles has random lifetimes.Anyone know how to controll emmiting with expressions based on pscale or lifetime?Let me know if i havent explained it good enough.This is sort of an extension to the https://vimeo.com/152083535 [vimeo.com] tutorial on boiling geo.thanks ToForums.hiplc
  11. Hi, I've tried it over and over. Suddenly the complete attributes are missing in the POP. I dont know the concrete circumstances when it happens. I think its different. Is it my fault, missing something, a bug? disintegration_v.2.hip
  12. Hi, I've tried it over and over. Suddenly the complete attributes are missing in the POP. I dont know the concrete circumstances when it happens. I think its different.
  13. Hi, I've tried it over and over. Suddenly the complete attributes are missing in the POP. I dont know the concrete circumstances when it happens. I think its different. disintegration_v.2.hip
  14. Hi everyone. Does anybody know how to use surface field in voppop or some dopvop to find the distance between my particles and surface. I want to make a force wind that depends on distance between surface and particles, so the farther point from the surface, the stronger the force of the wind. And the surface has really big waves for example, thats why i cant use just P.y for power of force for flat surface. Hope I explained it clearly)
  15. POP EMIT FEM

    Hey Guys, I am trying to get POPs to emit a finite element. I have a simple setup where I am birthing a particle every 50 frames and having this fed into DOPs where the finite element solver takes over. The problem is I cant seem to source more then 1 instance of the object into Dops. I have attached a scene file I hope someone can help. Thanks, Clive Balls_Test_Fem.hipnc
  16. I need to stick several million particles on their animated source geometry at the exact point where they are emitted from and follow the geometry's (emission point's) position. Please guide me towards any resource that might explain this process clearly. best regards
  17. Hi everyone, I'm trying to do a school of fish with a particle system that would follow a curve. Basically I'm emitting some particles and they move along a curve with a popcurveforce. By default the particles orientation seem to go along with the curve but since I'm trying to do a school of fish, I would like my particles Z orientation to always be 0 so the fishes don't swim on the back. So far I've tried with this expression in a popwrangle : p@orient.z = 0; The thing is it seems to zero out the orientation of x and y as well.. And I still want the x and y to go along with the curve. I'v tried with a popattract instead of a popcurveforce and I'm still not able to constraint the Z orient.. Maybe it has to do with something else than the @orient attribute since I don't see it in my geometry spreadsheet..? There's something I don't get! (Needless to say that I'm new in Houdini :P) Thanks a lot! test_fish_school.hiplc
  18. Popnet Kill

    Hello! I'm trying to kill points inside DOPs (well a popnet actually). The way I'd like to do this is by finding the closest point to the ground object (how do I reference an object in DOPs?) and computing the vector from the POP point to the nearest point, then dotting that onto the ground points normal vector. That's a nice way to figure out which side of the ground the point is on, then killing it. At least that works outside of DOPs. I'm wondering how I can do this inside DOPs because I don't want to post-process kill thousands of points if I can kill them in the simulation. Any ideas? Thanks, cw
  19. Particles collide inside a mesh

    Hello everyone,Sorry for the basic question but I just want to emit some bouncing balls inside a mesh with Houdini 15.5. To create that I just create a source particle emitter and I put it inside my collider mesh. I make the mesh a static object and increase the uniform division and click on invert sign in the static object node. But when I launch the simulation the particles have a very strange behavior. If anyone have some idea to achieve this.Thank you for your response. animation_particles_gpe_v003.hip
  20. POP Fireworks - Color from Image

    Hey guys, I have to create fireworks that turn into some specific shapes. Just like this: I have an workflow idea working with colors. It goes like this: -Simulate standard the fireworks; -Go to a specific frame where the where the starbusrt* is fully formed; -Apply the color at this specific frame; -keep that specific color assigned to individual particles through the whole simulation; (not working) does it make sense? I'm having problems to achieve this last step. what I'm doing is: -caching the simulation; -apply the colors; -add a timeshif to the "rest" frame (89 in this case); -copy the color attributes from this frame (89) to the animated simulation; I guess it happens because the particle count changes during the sim. Any idea on how to proceed? (Scene file is attached) Thank you, Alvaro *starburst is the round shape Fireworks.v1b.rar
  21. Hello, I was wondering if it's possible to create velocity vectors from an animated sequence (texture). Ideally something similar to Optical Flow. I can extract movement from geometry (eg. use trail to generate v vector of animated VOP) and I can do basic image analysis (eg. convolution kernel operations on coloured points using VOP) so I feel it could be kind of possible to do it but can't get my head around it. In terms of results I'd like to create a particle system that reacts to an animated texture (eg. overlay particles on a animated texture and have them follow the movements in the video) thanks!
  22. sand disintegration

    Hello, I'm trying to get a logo to dissolve/disintegrate into sand. Like it is made out of sand and something is eating out the outside shell and the sand is pouring out. In the attached file I was first trying to use a geometry and use attribute transfer to set the force of a popforce. as I would like to use in the future a more random/noisy pattern. I'm not exactly sure if my expression is wrong, if my whole set up is wrong. I tried to look around for tutorials or thread but couldn't find any. Any idea, suggestion or links would be greatly appreciated. thanks bil Sand_Desintegration01.hipnc
  23. Use Points as Particles

    Hi, Let's say I have a bunch of points that I have created, and I want to treat them as particles in a popnet - how do I do this? Is it possible to do this without emitting from the source points for one frame? I noticed that you can set the initial geometry for the popobject node, and gravity and forces do effect these points, but no pop nodes do anything at all. How do I get the pop solver to consider these points as particles? I have attached a simple example. (Note: The popsource node has the Geometry Source set to 'Use DOP Objects', but this is undocumented) Points_as_Particles.hipnc
  24. Hi does anyone know how can I add a hard constraint between two or more particles ? exactly like RBD objects but it should be work for POP solver. I prefer do this via custom VEX codes for manipulating P or V. Thanks S
  25. Hi guys, I've hit a bit of a wall in the new version of POPs. I have a deforming mesh (skinned character), which I have scattered points on. What I'm trying to achieve is a set of particles that are essentially locked onto their source point until a certain time or proximity from some sort of gizmo, and then morph to the position of another set of points. I have been able to achieve this in the old version of POPs using a position node, but it's rather slow. However I can't seem to figure out how to achieve the same thing in the DOP version of POPS. Any help would be great appreciated. Thanks
×