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Found 127 results

  1. I have a feeling this might be a dumb question, but I have been stuck on it for a few days now. Or maybe not so, as I've been looking countless treads here, but none really solved my problem. I've got a really simple setup, pop curve force guiding some rbd objects (I also tried doing it with points and copy stamping after sim to the same result). At a point in the sim the vectors start to point outwards: What I would need is for their direction to be always facing forward as they are at the start: I've had some luck with using pop torque, but still not what I need. I've attached an example file and the curve alembic. RBD_Directional_Vectors_Curve_Force.hip curve01.abc
  2. Dear community, I am working on a little particle system that I need some help with and I hope that you can help me out somehow: I am emitting particles from points A. These particles are attracted by another pointcloud B via POP Attract, with the attraction type set to points. So far so good. My question is now: How can I vary the attraction force inside pointcloud B for each point? Is that possible? I've been looking into and reading the docs, of course, but all to no avail. Does anybody have an idea on how to solve this issue, meaning giving the points in pointcloud B varying attraction forces? Is there an attribute that I have to apply on pointcloud B, that POP attract could use? Best wishes and merry christmas and Chanukka, Nicolas
  3. I am trying to blow up multiple groups of particles in a sequence.(boxes of confetti exploding at different times). The activation isn't really the problem as I can use a sop solver within a dop to activate the particles group at different time. The issue is to give them that "initial velocity" at activation time. The only method i found that is working to achieve the effect, was to actually import and merge many popobject and "activate" them one by one in a sequence , with the velocity attribute created at sop level This solution is of course very inconvenient. I attached a clean file, with just the different group all popping at the same time. a solution to have them delayed one after the other would be very welcome I just can't find an elegant method which works procedurally. Thank you for your help confetis.hip
  4. **I'm amending this--originally it was just the below question, about making POP particles collide with FLIP sims, but I just was toying with multiple POP emitters/particles in the same scene, and they don't seem to want to play together easier--so my more fundamental (surely stupider) question is: how does one make different particle systems (POP, FLIP) interact? For instance, in the supersimple screenshot, I would want the orange particles (which have initial velocity on x) to collide with the blue ones. I would think, since they're part of the same POP solver, this would just happen. I would think wrong.** I have a puddle of bood, a viscous FLIP fluid. I have POP particle rain (a la https://www.sidefx.com/tutorials/rain-systems-and-wetmaps/). How can I make the rain (the particles--I assume not the instanced geo) collide with/splash the FLIP fluids? I understand how to use POP forces on FLIP sims, but when I put a POPnet and FLIP sim in the same scene, they just ignore each other. Since static/RBD and particle (FLIP or POP) solvers all play so well together with minimal extra effort, I'm sure getting POP and FLIP sims to play together is something simple and dumb. Thanks!
  5. particle trails fading

    hey! sorry for the dumb question, but I couldn't find an answer I have a pop sim with some points, and I'm trailing them with the trail/add combo, it's all good but I can't find a way to map Alpha or color to the length of the trail to let the trail fade away, any idea? cheers!
  6. Hi everyone, Can anyone figure out how to do this stuff? I have tried many different ways but cant get it achieve the similar result. Down below are my approach, didnt really get colliding and sort of stacking effect.
  7. Crowd tilt avoidance on terrain

    Hi, I have little agent insects on a rock, sitting on flat ledges. I'd like them to wander, while avoiding steep slopes of the terrain. Does anyone know the best method to go about this? (FYI I'm fairly new to crowd- I was imagining I'd need a pop wrangle to use a look-at function, which would estimate the possible future tilt, then apply an avoidance force.) Any help is much appreciated!
  8. PARTICLES MOTION STOP

    HI, I know this might be an easy thing but i tried out and seems like i'm making a silly mistake. How can i make the movement of particles stop as it slows down?
  9. WATER DRIP

    Hi, I've been trying to make particles slide down a vertical surface but I want them to stop for a second while in motion, and then continue sliding again. I guess, I badly need help with this. Can anyone help me out ? I've tried animating the response feature in POP Behavior Detect but didn't work out. Each particle should have its own movement. Regards, David
  10. Hi, I want to emit particles from an texture just like in maya. I find the old thread here : but in houdini 16.5. That seems not work. . there are no " birth probability ",but "emisson attribute".And it says that it will use a point attribute.(but this will need very high mesh resolusion.) I fill the pic function in it ,but it returns an error. How to do this ? Thank you very much.
  11. Recursive Particle Split

    Hey guys, how can I duplicate particles recursively? Sort of in a fractal / l-system way, to simulate veins, bramches and stuff like this Thx
  12. Hello there, Is there any way to create Geo dynamically inside a dopnet? Specifically, i would like to have growing tendrils, and simulate those as they are created using popgrains. I created a popwrangle inside my dopnet, and created new points and primitives through vex. Unfortunately, that breaks the pop solver, as its not solving the newly created particles (However, if I put a force after the popsolver it works). I thought maybe that resetting the id to -1 (as used in a similiar way with the bullet solver) would do the trick, but unfortunately not. Is there any way that I can force the popsolver to recognize those newly created particles? Thanks in advance, Bajt createGeoinPop_v01.hiplc
  13. Points follow points

    Hello everybody! I would like to simulate particles on top of pre-animated / pre-simulated (cached) points. So far I only managed to do the "transfer v attribute inside a sop solver" trick. Unfortunately it does not give me the result I imagine. Instead of inheriting only the velocity I would rather like the points to be attracted by the pre-animated points so they tumble around and follow them the animated ones. Basically I am trying to animate some points and then do a simulation on top of it to give it a more natural feel and to be able to art direct the simulation better. I would greatly appreciate if somebody could give me a hint or a solution on how to do that? Thank you! Here is my current progress (particles inherit v): pop_transfer_vel.hiplc
  14. Pop Collision Ignore + Grain Solver

    hey guys, is there a way to make the Pop Collision Ignore node work with the grain solver? I really need to avoid the collision of one granular solid object, it works fine with normal particles but not with the grain solver. grains_avoid.collision_1.01.hiplc
  15. particle split loop

    hello, I have been try to make some effect by particles. I was trying to use pop network to make something like particles split. but if I use POP replicate. it only split once. How can I make particles split loop? just like 1 to 2 and 2 to 4 after that. I can't find a way to make it happened. thx
  16. Agent interacting with Pop Grains

    Hello everyone, First time poster. Coming from a C4d / Realflow background. I have been able to accomplish what I am trying to do with regular objects as a sphere or a cube lets say. I downloaded a zombie crawl from https://www.mixamo.com/#/?page=1&query=zombie . I imported the fbx into an agent and added an unpack node under the agent as I read this was the only way to be able to get it to react with RBD / Fluids etc. My scene consists of a cube with a transform on it to make it a rectangle which I applied a wet sand preset. The rectangle is above the imported fbx zombie. I have a ground plane. I tried making the zombie a RBD and I also tried making it a deforming object. The goal is to sim to grains with the zombie in place (I removed the $T animation channel). Once the grains seemed to be settled and looking like a nice pile of dirt, I spit out an initial_state.sim file. I added the to my dop network. I then selected the zombie and clicked on Awaken by Geometry. I also turned on Enable auto sleep and Start asleep on the pop solver. I am having several issues. I would like once I have my initial state, for all the particles to be frozen or "asleep" unless the zombie interacts with them. Also I was to be able to control the velocity of how his movements affect the particles collisions... and those particles would in turn AWAKEN more particles etc. I can not get any of those to work. I searched every post on the forum with grains. I learned a few things from Rohan Dalvi's tuts. So I am kinda stuck and hoping someone could help me out. I have attached the latest iteration of where I am currently (stuck). Let me know if you have any questions on my end. I just recently bought indie and redshift and loving it so far. Still wrapping my head around attribute wranglers and vex, but one day at a time. Thanks guys! William grains_zombie_crawl_006.zip
  17. Hi I am trying to do this old POP tutorial, there is a section where he takes the red color value and modulates it with a spline ramp. (around the 4 mins mark) For some reason I cant recreate this at all. He is using a VOP sop and I am recreating it in an attribute vop , i think that should work fine . when i connect my ramp it just removes all the color. Thanks https://vimeo.com/95644892
  18. velocity field question

    hello guys, I tried to get velocity field in to POP and use advect by volume. but particles stop moving when they reaching some position. I can't find the reason of it and how to fix it. Does anyone can help that for me please? vortex_field_problem.hipnc
  19. Noise in particles

    I sim a particle system, I want to put some nois after sim but Cd color is not baked at the particles, how can I baked it ? does Anybudy have clue ?
  20. POP Wrangle Group

    Hello, I want a second age ("myage") for particles, when they are in the group "active". Very simple? But it don't work
  21. Geometry particles PopSpin

    Hi all! I hope this isn't a dumb question, but I'm stuck getting my particle shapes to spin. I might be approaching this wrong... I've fractured and packed an object. I bring the pieces into the POP network, instancing each piece with source emission type set to All Geometry - each particle is a piece from the fractured geo. Now I just want these pieces to spin. I do get the w attribute set, but, the pieces themselves are just translating with the particles, not rotating. A simple scene with the setup is attached. Can anyone point me in the right direction here, and perhaps explain why this approach doesn't seem to be working? Thanks! popSpin.hip
  22. Hey! I'm scattering some points and then use them as first input in a popnet to sim it. in the pop source I'd like to just emit a point for every source point, so basically I'm emitting for 1 frame with the same number of points, to get the same points in the sim. is there a way to tell the pop source to emit the exact number of points you have as input (at the mo I'm just manually putting the number...) ? cheers!
  23. Hello! I'm using grains to fake cloth and I'm having this weird issue where I'm using a popwrangle to update my targetP (because the constraint points are animated), and it seems to be dragging the target points towards the origin? I've compared my set up to a couple example files and can't quite figure out what's gone wrong. Any help would be appreciated! Example file attached targetPointIssue.hiplc
  24. Hello everyone! I'm just wondering if someone knows how to create that a Particles meets and other particle stick togheter, and if is possible to made that. If there is a particle floating around and get close to an other particle floating around can they stick togheter. or any way that I can aproach that?
  25. Particles

    Hello everyone! I'm just wondering if someone knows how to create that a Particles meets and other particle stick togheter, and if is possible to made that. If there is a particle floating around and get close to an other particle floating around can they stick togheter. or any way that I can aproach that?
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