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Showing results for tags 'collision'.
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Hello all, Maybe a dumb thing, but I can't figure it out right now. I rebuild a simple setup to understand the issue (you will find the file attached) I have a simple wall that I want to break (RBD SOP) I created a sphere emitter on the other side, with RBD bullet solvers too (RBD SOP), and switches ($FF%20==1). Plugged this one into RBD (wall) for collision. Issue : Only my first sphere is taken in account. 1) Do I need to use DOP ? (didn't figure out the setup yet) 2) I guess as the sphere are spawn over time, the solver can't understand the data ? Let me know your thought. Thank you RBD_Emit.hipnc
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Hi. what I'm looking for is quite simple. I am trying to ignore/exclude the self collision between certain grains. Let's say i have blue, green and red points as grains. I want the blue grains to collide with red and green but not with blue. I tried adding collisiongroup and collisionignore but it only seems to work with external colliders. is there a way to do this?
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Hi guys, I'm trying to get bubbles to collide with each other but can't seem to find the solution yet. I'm using points that are emitted upwards and assign a random pscale value to each new point. I'd like points to change colors when they are too close to each other, that way I can check if the setup works. So when 2 points are close to each I'd like to check if the distance between them is not smaller than the radius of the point and the radius of the closest point. If it is, then the points need to turn red. For now, all my points turn red, but I think it's because I can't find a way to access the closest's point pscale value to compare it with the distance. Can someone guide me on how to approach this kind of issue? I tried to use pcfind but that doesn't seem to work too . Bubbles_WIP.hipnc
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Hi guys, I just want to ask one quick question. I am using bullet solver and want to count hit value of pieces with collision geomectory. I tried pop collision detect also but its not working on rbd. thanks
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When you create the collision vdb for a flip simulation or a pyro simulation or a pop simulation, do you turn on Fill Interior or not? And why? The Static Object and Deforming Object shelf tools don't turn it on. Does that mean that this should be the proper way? Are there such scenarios where you specifically need to turn it on or off for your collision to be working properly? I am full of doubts.
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Hi, I'd like to set up a simulation where there's a small container, and half of it will be filled with liquid. The initial state of the liquid should be static, like a cup of water left on the table for a long time. Then I'll introduce a rigid object to collide with the liquid. Sounds simple, right? But what's puzzling me is how to achieve the static state of the water before the impact of the rigid object. I created the container and converted the lower half of its volume into flip particles, then applied gravity. What happened next was that the behavior of the particles at the collision volume junction wasn't as normal as expected. They kept jittering, and as the simulation continued, the jittering became even more intense. Whether it's what I expected or what happens in the real world, the water should become more and more static as time goes by. However, with gravity turned on in the DOPNET, I can't make them completely calm. I found that if I adjust the size of the flip solver volume limits to replace the role of the container and turn on the flip object's closed boundary option, the particles at the boundary junction don't jitter as much. As time passes, the performance of all fluid particles becomes increasingly calm. This is exactly the effect I'm looking for. However, this method only works with cube-shaped containers. If I use a spherical or tubular container, it doesn't solve the problem. So, how can we truly eliminate the jittering of flip particles at the collision volume junction? Below is my .hip file. Thank you all very much. TANKtest.hip
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One more Flip collision question. External colliders work as expected. But how do you get the interior of your geometry to act as collider? For instance a simple box that wraps your fluid source. The goal would be for the fluid to fill the box. What edits need to be made to either the geometry or Collider Source for this to work?
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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
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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
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when I simulation fluid in Houdini, some particles just pass through the colled object. what should I do?
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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
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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
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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
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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
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Why static object is not working in popnet
Ansh Kathuria posted a topic in General Houdini Questions
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.
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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
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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
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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!
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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..
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Hi, I would like to create an animation of blooming flower. I've created the basic setup, but I have a problem with intersecting petals. Does anyone have an idea how to get rid of those intersections without deleting whole petals? Thanks in advance for all the answers. flowertest.hiplc
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Hey guys, I'm having some issues with a FLIP collision, seems my VDB collider boundaries are affecting the sim, anyone knows what can be causing this? I'm using static object + static solver with a proxy volume as collider. Thanks!
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Hey guys, What is the best way to use the slip on collision control field, to avoid viscous fluid of sticking on objects? I managed to do it with the help of a friend, using the gas match field + a source volume. it works fine for static objects but not at all for moving ones. I have a project with an alembic animation and I really need to use it on the animated surface. Can someone help me? Here's the setup in dops: Here's it working fine with a static object. It's a top view and the red box is the sliping object: and here the red box is animated, not working: Not sure if this is the best way to approach it so any other ideas would reeaally help me scene file is attached Cheers, Alvaro flip.slip.v2a.hiplc
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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
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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
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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
