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Found 38 results

  1. Texturing geo after sim

    Hi everyone, I hope you are all well during these times. I have a quick question to ask about texturing a re-meshed grain simulation. The UVs of the mesh change and thus throwing the texture UV space all over the place. Is there a way for to remesh the grain simulation so that the topology allows the texture to stick to the geometry? I can provide the file if it helps. Thank you very much, your time is appreciated.
  2. Howdy folks! I've recently started looking into Vellum and I am currently trying to create interaction/collision between Vellum grains and Vellum Hair however it does not seem to come as easy as interaction between grains and cloth. I've used the same setup that worked with my grains and cloth example to make this setup however as mentioned above so far I've had no luck in making it work. I am sure that there is something very basic that I am missing here but I can't seem to find it. Any ideas? Screenshots of the setup(Sorry for less than optimal/clean node layout): Scene file as well as base model too if you'd rather dig into it. Vellum_Hair_Grain_Test.zip
  3. Hi; After simulating a "Vellum Grains", how can I create a surface (volume) from it? Thanks for helping.
  4. Hello! I'm doing a school project, and I have to create something like a slime mesh. The main problem I have, is that I get a lot of flickering when I try to mesh the vellum grain using the particle fluid surface node. The same thing happens when I'm trying to mesh flip particles. Does anyone know how to get rid of this flickering? I've been searching a lot but can't find an answer. Thanks!! StickyFluid.mp4 bloodRND.mp4
  5. @pscale for vellum grain?

    Does anyone know if it's possible to use @pscale for vellum grain? I mean to create it on "Grain Source" and pass it to a "Vellum Configure Grain". To a "grain size" probably? Thanks. BK
  6. Vellum Grains

    Hi, I have been trying to understand the operation of vellum grains for a few days, I wanted to make a falling sack with sand as on the sideFX side, but when breaking the material it explodes. Maybe anyone will be able to help me? https://www.sidefx.com/docs/houdini/videos/VellumGrains.mp4 adds a file can help something vell_with_grain_v3.hipnc
  7. GRAIN STICK ERROR

    Hello Dear Houdini Community, I have been trying for hours to solve this problem. I have a simple simulation with grains, the basic idea is when the particles touch the surface more often they stick to it. they do not do that, they all disappear to one point in the scene, actually always 0, Y value, 0. Can someone look at it? Sincerely, Tim grain_test_collision_stuck.hip
  8. Houdini grain solver

    Hi, I'm trying a stage on Houdini. A castle made of sand is moving upwards. After 25 frames the castle falls down and collapses. my question is that I want the castle moving upwards at one side and falling down at the other at the same time. Thanks for your help. testGrain.mov
  9. Hi I was trying to create an effect of cloth pieces sticking to an animated object on contact. However, it seemed to release and re-attach every substep. Sometimes, they "creep" on the collision surface. These are the goals I tried to achieve 1. Dynamically attach to deforming collision on contact 2. Dynamically delete the paper if they fell under y 0. (done, thank to Toadstorm's post 3. Make the attached points static (pin to animation?) if possible, to reduce calculation cost. Here I attached the hip I'm working on. test_vellum.hip
  10. Vellum grain (particles awake by collider)

    Hello, guys! I'm new in houdini. There is a simple question: how to activate particles using a moving collision object in vellum solver? When I activate the Enable Auto Sleep (inside the Vellum Solver), the collision disappears. I tried to add a popcollisiondetect in vellumsolver/dopnet/forces, and somehow connect Cd from there with the attribute doautosleep (from Sleeping) but nothing happened. http://prntscr.com/lqbfyr And one more question: why the popcollisiondetect invert my colliders in the space (blue spheres)? http://prntscr.com/lqbi76 I would be grateful for any advice
  11. pyro explosion using grain

    hi, am working on an explosion shot (desert explosion). i have seen some grain adverted pyro examples . can anybody give some tips doing it ?
  12. When would you use FEM over Grain? The last couple of weeks I have been working with Grains, and got a good understanding of how it works. It seems that you can do pretty much everything with this tool in case of cloth and simulation of object that will deform. I haven't been using that much time on FEM, and from my perspective it looks like a tool that has a lot of overlaps with the grain tool. It could be nice to get an understanding of where the FEM and Grain tool differs and where to use which, from people that has good experience with both tools.
  13. 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
  14. I've been stuck on this for a couple of days now and would love to hear you guys' input. I have close up shot were a character's feet is pushing through snow up to his ankles. I decided to try grains for this (it's my first time really using it) and to get the snow together I used the constraints set outside in the grain source. Mostly the sim is working as intended but I'm getting a lot of unwanted fast movement from some particles (as if they're trying to keep the constraint but not really keeping it, so they pop in and out, and that results on a flickering on the meshing. Did anyone come around this problem before? I am up for any solution at this point, even trying another method.
  15. Caramel Goo Tear Apart

    Hi everyone, my first post, newbie to houdini but diving in! ive been trying to find the best way to achieve the classic mars bar chocolate caramel bar being pulled apart in close up detail, where the caramel slowly tears apart with strands becoming longer and thinner as it gets pulled. kind of like the classic bubble gum on the shoe type thing. FEM ive tried fem, but couldnt get it to become strandy enough and then completely tear apart. love to know if i continue to explore fem that it would be possible to make this effect. GRAIN SOLVER?? perhaps the grain solver with some noise determing the glue strength so natural tears become apparent in the grain block as they get pulled apart? FLIP: VISCOUS FLIP viscous sim perhaps might work? anyone experienced think this could be the way to do it? im hitting lots of newbie dead ends, so any help on which avenue will actually get me the desired effect, id be much appreciative. J
  16. 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?
  17. 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?
  18. snow effects with POP grains

    hi, I try to make snow effect with grain solver, started from wet sand shell, wetness=1, and changed clump stiffness to 100. After tweaking around parameters, I got 3 main problems. 1 – how to add friction to static object? I set friction 10, bounce 0 , but particle is still sliding a lot. 2 – When dynamic object collide grain particle, it pushes away too much, but should not influence to surrounding particles. I think constrain pushes away in order to keep space between particles. 3 – particle motion is kind of springy or bouncy. Snow should damp velocity immediately. I guess I need to figure out how to control compression or density of particles by grain's internal constraint?! If anyone knows solutions, it would be great, thanks! grainSnow_v01.hip
  19. Sand Grain Interaction Help Needed

    Hey folks, Hope all is well. Working on a close-up shot, Where a snake penetrates through some sand. I like to achieve a gentle and realistic interaction between the two objects, Effects of sand rolling on the snake and each other is desired too of course. However I'm clueless of how this possibly could be achieved. Please check the attached scene below. , Any help or hint would be greatly appreciated. grain_init.hipnc
  20. Grain RBD Active/Deactive

    Morning all, I've got a basic Grain RBD setup of a box filled with grains I would like to settle and then stop movement until a collider is introduced. I 've used a pop wrangle to deactivate the grains below a velocity threshold but would like them to be reactivated once the collider is in close proximity. I thought a simple SOP Solver with an attribute transfer would do the job but, although the spreadsheet says their active value = 0 - they are clearly still active and the SOP Solver appears to be overriding the POP Wrangle completely. Any suggestions on either why this doesn't work or a better alternative. Thanks basicGrainRBD.hip
  21. Hello folks, Newbie here. I am trying to make some foam particles with POP Grains. So far the motion is coming along well what I am missing is the particle spin based on clumps it has formed. In Maya Nparticles the particles rotation is computed dynamically. I wonder if there is a way to do the same with POP Grains & link the rotation or spinning speed based on the clumps. Any Idea or workaround would be great ! Thanks, Vik
  22. 2D dynamics

    What's the best way to simulate dynamics with just 2D shapes? Is it possible to use any of the existing solvers to simulate rigid bodies, but also flexible curve/polygonal shapes that respect line to line collisions ? I've tried using the wire and the grain solver (with rest length on a network of lines that connect the points), but the collisions only happen on the point level, resulting in penetrations between shapes. Is there anything else I should look into, or a working example I can take a look? thanks a lot georgios
  23. Grain particles explosion

    Hello I have a very strange situation where the grain particles suddenly explode along a line!.instead of volume collision I used "use surface collision" for collision detection for the body of the butterfly .as you can see there is no problem, but right the next frame the particles explode in such a strange way that I couldn't figure out why. I checked the setting for dozens of times... I found nothing wrong.I have other simulation with the same setting, It is worse.please let me know If something's wrong. thank you in advance
  24. Hey, Super new to Houdini here. Trying to stray away from my comp education and go into FX instead. We just finished a group project and it's time for summer break so I want to go back and do FX for a couple of finished projects of other groups to get finished comped shots to build a FX reel. For this particular project I wanted to make a grain simulation for a group that had a hermit crab switching his shell on the ocean floor. The finished project contained just a mesh with a sand texture on it together with stock footage for some dust and smoke when the crab flips the new shell from the sand bottom. I have attached my super quick way of re-doing it by following mainly a tutorial about the grainsource/grainsolver adjusted to this scene. My further a long hip is not that much better off anyway and much messier with much trial and error. Main problems are; -The particles keep moving for such a long duration even though I have friction parameters set to 1. Maybe the sim just have to run much longer? -Size of particles to represent sand obviously has to be quite tiny so I'm a bit unsure if I will have to scale them down all that much and create a super thick layer that covers all the way down to the tip of the shells flip animation (at ~54F) that to me looks like I'll be in the millions. -Camera seems off. I was reading up about camera exporting from Maya and asked a former student at my school that has been at an internship working with Houdini that said Null scaled to .001 is fine but it doesn't match the final shot. I will also have to double check this with the group that provided me with the assets. Still nice to get clarification. -Underwater gravity for the stones. I assume transfering Cd to the particles getting hit by the shell and then add a POP Force group that lowers the gravity specifically for those particles? -Maybe not such a big issue but particles clipping on the ground plane. -I also don't seem to be able to give the grains a shader/material like in the tutorial I watched. I have no idea what I'm doing wrong here. Just adding a dirt slaps it in /mat and gives it to everything except my particles. Although that works when doing the dop import afterwards when everything else is removed anyway. I have attached the hip file a long with the assets I have received from the group. cstSand.zip
  25. Constraint Grains to Animation (targetP ?)

    Hey guys, how can I use this target pins option? I have an animation in sops and I need the grains to be constranited to that animation. I guess the targetP attribute shouldn't come from Sops but I can't find a way to make it in Dops beased on that Sop animation. Any tips? Thx
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