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Found 173 results

  1. Hi guys, I tried to use "RBD Packed Object" + "FLIP fluid" and as you can see in the image bellow, the boxes sink into the fluid after a while. How can I fix it? The DOP creates some volumes inside the boxes, and I guess they are somehow a collision volume representation, but I don't know how to increase their resolution. As soon as the volumes disappear, the boxes sink into the fluid. Thanks for helping. Floating RBD Packed object_01.hip
  2. Need collision data from box on those lines to Sop Level or Chops ---whats the Name of attribute that i searching ??? Thanx for any Help colldataCV.hiplc
  3. Hi guys, I tried to use the "Detangle SOP", but it doesn't work correctly. It moves the points on the line's intersections, but they are not detangled (I think it has to move the points in the Y direction, too)... How can I fix it? Thanks for helping. Detangle.hip
  4. flip simulation collision

    when I simulation fluid in Houdini, some particles just pass through the colled object. what should I do?
  5. Hello, I am trying to make a shelled object with a thickness (so negative space outside and inside, but the thin shell is positive space for collisions) collide with a FLIP fluid sim. Essentially imagine an egg with some fluid inside. The fluid would stay inside until cracked. After that point the water spills out and the collisions of the shell are all accurate before and after the crack. The problem im facing is that VDB creates only either a fully encased volume where anything thats inside the egg is negative and outside is positive or vice versa. I cant seem to make it recognize that the shell is the only thing it should be making a VDB volume out of and treating everything else as the outside. I can turn on the invert sign on the collision for FLIP and it kinda works but then once the egg cracks it just all goes haywire. So Im not sure how to approach this. I have also tried to create two VDBs with slight offset and combine them with the multiply function. Which in volume slice shows as a narrow band but the FLIP particles dont seem to like it at all. I have attached a simple file to show what's happening. Water_test.hiplc
  6. I am linking my Houdini project file for you guys! Please take time and analyze my blunders, trying hard to make this project. I am having problem with my project which i am making for my portfolio, but one thing has blown my mind in pieces since few days now, so sad. Here i have done Ground fracture and simulated all the fractured pieces. But when i am trying to make Debris pieces collide with my Static Object(i.e. Ground Fracture), then it won't collide and by ignoring that, fall down. Particles are not colliding with the Static object. I have tried each and every step i know to solve this but particles are not colliding. I tried by making the ground VDB and then make volume collision on Static object, that works but it plays the simulation too slow that i can't even analyze what is happening. Please help me guys, From my side i have done everything i know. Your support makes more value to my project, Thanks in Advance. Ground_Fracture19.hip
  7. Hi, I'm trying to remove objects and collision objects from an RBD Bullet Solver simulation. Removing objects work inside the node connecting a geometry wrangle to the presolve output using 'removepoint' with the packed rbd geometry. I try to do the same with the collisions, but I'm not sure how to access the collisions from the geometry wrangle. I also tried the Collision Geometry input of the RBD Bullet Solver, and use a switch or move the geometry of colliders, but it does no seem to work. Any suggestions would be appreciated. Gabor
  8. Hey there! Please anyone help me with this, When i make the Static object node in the "popnet", then the particles i created does'nt collide with that ground or static object. I tried many ways but the collision is not happening with the particles and static object. Here i have a ground which is subtracted(By boolean) from the main ground which is being fractured and the main ground is emitting debris, but whenever i use static object and import the ground to be a static object there, it won't collide with particles. Why is this happening and what is the best solution for this ? Here i linked 2 images where you may understand what i am trying to say. Anyone's help will be appreciated, Thanks in advance.
  9. Hey there, I have a simple setup where I generate a bunch of particles and let them drop on some spheres. I would like to achieve to change the Color of the Spheres based on hit by a particle. With hitprim I was abled to change the color of primitives of the spheres but I would like to check based on the selected primitiv to select the whole Object. Also I would like once changed from Black to Red to keep the color even after the particle passed through and left the object. And on top of that, if possible to add some delay. So once the particle hit the object it takes like 10-15 Frames till the spheres changes color best with fading to that color (but not sure if that is possible).. Has anyone an idea how to achieve that or is there a different way. I tried with attribute Transfer but couldn't get it to work. I uploaded my current setup: Particle_hit_detection_changecolor_01.hip
  10. Hello guys, In a simple RBD simulation, when I replace the "Ground Plane" collision DOP with my Collision-Box, the rigid body objects never stop moving! How can I bring them to stop? (When I use the "Ground Plane" node, everything is ok!). I tried to use the " rbdautofreeze DOP", but it doesn't work. Thanks for helping. RBDs_01.hip
  11. Hi all - basic FLIP question around detecting particles that collide. I have a simple setup (see screenshot) and I need to detect and group particles that collide with the static object in order to assign a new Cd to these collision particles - hopefully determined by either a ramp OR a texture color from the collision geo. I'm having trouble finding good references for detecting colliding particles in a flip tank / flip solver setup. I found several tutorials covering setting up a pop collision detect node for a pop solver, but I'm unsure how to translate that to a flip solver - or even if a pop collision detect would work with a flip solver. Any help or pointers would be much appreciated. Thank you!
  12. Hey folks I have set up a particle simulation where I have then attached a pyro sim to it (through the rasterize attributes volumes node)... Also I have imported a few objects where the smoke sim should interact with... Everything is fine, until one point: When I am wanting that the pyro sim should collide with the object (seen on the screenshot), then the smoke is just going through the "wall of dirt" (its just a wall with some grass and dirt... ) I just need the collisions so that I can then export the smoke simulation as a vdb sequence... What I have tried so far: - I have give it more thickness with poly extrude node (also added the collision guide thing to look if everything is fine) - also I have increased the substeps on the smoke sim - I have add a object merge node in the pyroFX node (as seen in the screenshot) - just ignore this one node where I have add the red line... But everything I've tried so far, I got no luck to fix it..
  13. 2d rbd collision

    HI.i want to reach this effect like this first gif shows. i have get this like second gif shows. i attach my sence file.hope you guys could give me some suggestion. thanks in advace. 2dBBD.hip b
  14. 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
  15. Hello all!, I am trying to create two different flip sims, which should collide with each other. Sim A is a flat tank, with a suction force and some vortex force. Sim B is a simple sphere emitting fluid. I want Sim B fluid to collide with Sim A fluid. Problem is if I do these inside one DOP network, Sim B inherits all the forces attached to Sim A, I am trying to prevent that. Maybe I'm overcomplicating this whole thing. Any ideas on how I can get them to collide with each other? Please refer to the attached hip file. Thank you all for your time. TwistForce.hipnc
  16. Hi guys. In a smoke simulation, I want to use a thin deforming geometry (a sheet) as the collision object, but instead of creating a Volume, I want to use "Point Velocity For Collisions". Is it possible? Thanks for helping. Smoke_CollisionPoints.hip
  17. I'm trying to create an animation of a ship rising out of the water and simulate the water on it. But the animation is so fast that sails and thin ropes are not recognized as collisions. Perhaps raising the substep is a good idea, but is there any other way? Ideally, the collision should be as clean as this
  18. Hi everyone! I'm struggling to get rid of those sharp voxels in the sim. I have a pyro solver, and I have tried increasing a lot the res in the Volume Object, Volume Rasterize Attrib, Points from Volume, increasing substeps, also the collider has a very decent mesh and it's also subdivided. I also tried using the collision object as a proxy vdb, and also using it as a collision volume inside the pyro solver. It's been very frustrating. I also found other posts with the same question, but still without any luck after all I have tried. I know the collision object may be causing all of this voxelization, but I keep on increasing the res, and I'm still getting the same results. Any help on this will be much appreciated! Thanks untitled6.mp4
  19. Hi there, I'm trying to understand Dopnet a bit more in depth and try to understand a bit better how you can transfer data from one object and use it in another. While playing a bit around I ran into a problem where I don't understand why this isn't working. I created a simple particle setup, and after a hit of a particle, a sphere is created into another object (called 'col_gen'). What I try to do is using these spheres in the next frame as a collision for the particles again. But somehow I can't get it get to work. Simple as that, right? What I did try is using the path "../:col_gen/Geometry" in the soppath of the static object. That doesn't do anything. So I tried to reference the geometry into an sopGeo node, and apply that data onto the staticobject. But that doesn't work neither. Question 1 is: Why doesn't this work like this? And question 2 is: How would you solve this problem? Cheers, Sander (The hipfile is hidden underneath the screengrab) generateCollision.hip
  20. Hi, I wonder if it is possible to trigger an animation on an event. Let's say I have a sphere, I simulate it falling on the ground just using a Dopnet and a ground plane as a static object. And let's say I want to play an animation each time the sphere touch the ground, like waves on some water. How can I do it ? I've heard of RBD Impact Analysis, but I can't find how to use the generated points for something like it ? Can someone help me ? And can I have an example file ? I link an example of wave that I want to trigger when the sphere touch the ground Sound_Wave_v001.hip
  21. 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.
  22. Hello, i need a little help : I have a moving object with a scatter on it to create hair from these points. Theses hairs are stick with "pin points" and "match animation". And I would like to have hair collision with the object. But if I put this object on the collision input, there is a kind of artefact to these roots points. So what could be the solution to avoid this problem that is probably coming from pining AND colliding at the same time. I'd like to keep the pin system (no "attach to geometry"). Any idear ? Thanks
  23. I am simulating a beer overflow and somehow I can't get all the particles to slide down the collision geometry, which creates artifacts when meshing the simulation. Friction is set to 0 for both the flip object and staticObject (not animated), stickOnCollision on the flipSolver/volumeMotion is off and I have also set collision detection to none under the flipSolver/ParticleMotion Any ideas of what to try? Thank you (All the blue particles on the side of the pint don't move much towards the end of the sim)
  24. RBD collision Geometry

    Hi Everyone! I have a problem with collision geometry in the rigidbodysolver not moving. I have animated geometry I am plugging into the rigidbodysolver for collisions however I am finding it is remains static when I run the sim. The Initial Object Type is set to 'Animated Static' (although I have tried the others) Does anyone have any suggestions to get this collision geo moving again? Thanks sooooo much!
  25. Hi, Anyone know how to create this effects with the new pyro solver (geometry node)? On the static Object you had to click on "invert sign" but I can't find that on the new solver I just started Houdini sorry if my question may seem stupid Thanks all
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