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Found 49 results

  1. Hi everyone, I'm currently working on a blast/pyro effect, and I need some advices about fast colliders. I've fast moving collider that doesn't affect correctly my pyro. the solver seems to be unable to correctly evaluate the motion of my object. Any idea about how to solve this problem. I've a simple animated VDB collider (2 fileds vel and collisionvel) Cheers Bertrand
  2. Hi people! I'm learning some things in Houdini to create HDA's for cinema 4d or export vdb's simulations to render in c4d. In this case, I want to make a smoke simulation but I have one basic issue that I'm sure it solves with a simple way. I have one torus emitter inside of a tube but the smoke doesn't respect the tube geometry, It moves through it. How can I fix it? Thanks!!
  3. Hi! I'm a student learning Houdini, and I love it! Now I'm stuck with a problem. I want to use only one flip object that emit every frame from an animated particles source. At the first frame there's a 'base layer' of water that get emitted. The problem is that when new particles are added, then don't interact with the 'base layer'. Any help on how can I make the new fluid interact with the old one would be appreciated! I've attach a demo file with the same setup I use. FlipObjectBug.hip
  4. Hi Guys, I need some expert advice and insights on this project I'm working on. I'm doing some RnD first before moving to bigger scale so I can provide you guys with the HIP file. The objects however (barrels and table pieces) I cannot share with you. But maybe there's something in the dop nodes or solvers that you can spot right away. I'm working on a flood scene where there's a lot of debris and rubble that needs to be transported by the water. Please have a look at the video. The barrels seems to acquire a spin which at one point is out of control! I can imagine this could be the rotational stiffness... but the exploding (and stuck) piece of table is still a mystery at the moment. As you can see I'm also having trouble controlling the buoyancy of the objects in the fluid. Right now I use the density to try and float pieces but it's not entirely working the way I want it. To sum it up: - The wooden planks need to float - barrels need less spin and need to be embedded more in the fluid. - the tables obviously need to stop launching like superman . any advice or tips are greatly appreciated . High-RBD_count-in-fluid-006.hip
  5. Hey, I do have a little problem with flip collisions. I'm simulating a layer of caramel on top of which I want to add a layer of chocolate. The mesh of the first layer I converted to a deforming object. Collision volume and everything looks just fine. Unfortunately flip is going crazy when it touches this surface.
  6. Hi there, I've got some strange problems with the collision volumes in flip. The static object itself shows a clean, closed volume; the flip object on the other hand shows me a mess. Nothing is closed, the collision volume seems to be made of stripes. How does this discrepancy between static object and flip object happen regarding collisions? Actually the flip particles are floating inside the object. Got a new ship model and obviously some diffuculties making it work I also tried to use for each loops to convert each single object the shi is made of into volumes in order to merge them together insteat of turning the whole thing into a volume at once.
  7. Hey guys, working on a destruction shot which will involve a dragon thats being animated currently landing and somewhat destroying the building i have - Did tests with dropping spheres etc to get the constraints as i wished, then brought in a very rough 'previs' level peice of animation of the dragon i did - and as you will see from what i provide it doesnt collide correctly - i have tried increasing substeps - my collision volume matches my mesh almost perfectly, so really unsure what the issue maybe? Any help would be great (alembic and hip file below) and the youtube video link is to the latest flipbook i have showing the issue (please excuse my terrible dragon previs animation) Destruction_v2_t1.hip dragon_previs.abc
  8. Hey everyone! It's been a while since the last time I posted here because I was a little off from doing FX, but now I'm back on learning and stomped on some difficulties trying to do some collisions, flip and RBD simulations. The problem is that everything goes fine until a certain frame and the next one everything is exploding. I'm not sure if I'm not feeding the proper collision to the simulation or if the external forces override the movement of the particles rather when collision with a geometry takes places. A brief description of what I want to do is to achieve somewhat this kind of effect: -Water being pulled updwards, colliding with an object and continue the fluid simulation motion from there I'm attaching the .hip, some screenshots and a reference for what I want to do. Thanks a lot for taking a look and if someone can point me in the right direction I will be very grateful. Cheers! kamigawa_v002.hip
  9. Hi All, I have a working FLIP sim of a water fall that is colliding with my terrain mesh. I have added whitewater to the simulation and when I visualize the GREEN spray particles I can clearly see that they ignore my collision object. Is there any way to make the GREEN spray collide with the same surface as the WHITE foam?
  10. Hello artists! I'm trying to create an airfield alike effect but for geometry. Kind of like this effect : vimeo link Im also using VDBs for collision How'd you guys tackle this? Cheers and good work!
  11. Hello guys, I didn't get any answers from the sidefx forums so I'm trying my luck here. I am simulating urine from a medical cup going into a toilet bowl. Obviously, the water in the bowl is going to be clear, while the urine would be yellow in color. So I will need two separate objects to bring back into Maya for rendering (this is necessary). My current setup is successfully colliding with each other (the urine and toilet water). I am not sure what the correct way to set it up was, but this is currently how it is set up: * Urine fluid particles are sourced from a flip tank sop that's pruned– to match the shape of the cup that's holding the urine. That is then imported into the autodopnetwork through the flipobject sop and put into the first input of the flip solver. * The water in the toilet bowl is sourced slightly differently. For this one I did the same process by making a flip tank, pruned it and then made that a vdb and used the fluid source sop. This one is put into the fourth input of the flip solver. The reason I did this set up was I just could not get them to collide with my previous method. I tried making them both into flipobjects and merged them with mutual collision (i also tried left affects right) but they wouldn't interact. With the current set up, they do. Now I am wondering, how do I isolate the two different fluids so I can export them as separate objects, is it possible? Would appreciate some help, thanks!
  12. hi everyone i have a small issue here with my sand grains (wet grains) - i'm trying to get my mesh to collide with them but they seem to be jumping about a fair bit as the character moves. I'm not sure what i can do to adjust this jumping about does anyone have any ideas? playblast below to show you what i mean. I cant share the scene file right now sorry but the jumping of particles is quite noticeable here ip.mp4
  13. 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
  14. I am building out a Big Bang collision. I have a very large sphere that I use as the all encompassing universe. This is a static object. It is the Universe Sphere. I then have an RBD that I set the "center" parameter/attribute to the Universe sphere center channel. This sphere serves as the Big Bang, which has been fractured via Vonorni. I use a smaller sphere, whose "center" parameter is also set to the Universe Sphere center channel, as the initiator of the collision. I set the radius up for the Spheres. The Initiator Sphere is key framed with a Uniform Scale of 0 and then the very next frame it is set to 1. The size of this instantaneous expansion sets the velocity. I set the mass of the Initiator Sphere way up and I use a Position node to keep this Sphere for the most part locked down. I set bounce to 0, rotational spin to 0, and friction to 0. Over all, these settings, for the most part, keep the Initiator Sphere locked at the center of the Universe Sphere. However, I am getting a very slight wobble, before the Initiator Sphere settled down into a perfect center in reference to the Universe Sphere. What I am asking is what is the most efficient way to stop the wobble and lock the Initiator Sphere to the center of the Universe Sphere. I have looked at Constraints, however, the universe sphere is a static object, not an RBD, so I am thinking constraints will not work. I am looking for a very uniform collision across all out ward moving vectors, much like a uniform nuclear detonation. Any help would be much appreciated.
  15. I'm creating a white water effect, and was stuck at this point: there are streak effects on the white water. And in the snapshot, you can see my network connection. It seems that there is a rectangular outline around the boat.
  16. I can't work out why the particles are blowing up within my scene. I've changed a lot of a lot within the scene such as: scale, particle separation, collision data but nothing seems to stop this from happening. The file attached is my project. Thank you! pirate.zip
  17. Hi guys I'm doing a cloth simulation and I have some problems with collisions as you see in the image. I used volume sampling for collision and it is too heavy and doesn't make a difference so I used a proxy with surface method. I can't send the hip but this is my settings for cloth solver: Min Substeps: 1 Max CollisionPasses: 2 Can you guess what is the problem? Is it collision subdivision or something else? Thank you in advance
  18. Hi,I've been looking for answers for days about that issue but I can't find anything anywhere on that matter. I don't have any collision happening between a cloth object and a solid object but they are both on the same finite element solver, so why doesn't it work ? I asked a friend of mine to try and it's the same, he can't have collisions between a solid and a cloth object. Does something changed in v15 ? I've watched tutorials on cloth but they were on v13 so the solver was a bit different and I didn't find any tutorial on cloth for v15.On a forum a member shared a file that was supposed to work but it didn't, the piece of cloth went straight through the solid, no collision.Does somebody have information about that issue or do I have to add some node to enable the collision ?Thank you,Rob
  19. Hi everyone, how can this two have collision relationship with each other? I thing this is really simple, but I can't solve this Drops_Collid.hip
  20. Hi Thank you for visit this topic. I started learning about Houdini lately. And I have two questions. 1. I made a test scene for smoke, but I couldn't make collision between smoke and rigid body object. 2. I couldn't rendering smoke,(I think, because I didn't set shader on smoke But I don't know how to do) I know it is a stupid question but I need help. I upload my test scene so, please check it If you don't mind.(And If you find weird node network in my scene I'd like you tell me, I want to improve them PLEASE!) Thank you and sorry for bad English. smoke_collisionTEST.hipnc
  21. Would some kind soul please be able to show me the correct way of using the collide relationship dop in order to create 2 collision objects that will collide with everything else in the sim (like a fractured wall or similar), but not with each other? I'm sure the answer lay here but I'm not having much luck setting it up. Have attached a basic hip. At the moment sphere2 collides into sphere1 as I'd expect, then both go on to hit the wall. What I'd like is for sphere2 to pass through sphere1, but both spheres will still hit the wall. Collision_relationship.hip
  22. Hello. I'm having a problem trying to make viscous FLIP fluids collide with an alembic mesh. When the geometry approaches the fluid, the fluid collides with some kind of "bounding box" instead of the object itself. I've tried different collision approaches, proxy volume, surface, ray intersect... I've also tried changing the Collision Detection method on the FLIP solver, and reducing the surface extrapolation. I can't attach example but I hope the question is self explanatory. Thanks in advance.
  23. Hello everyone. I am facing a problem with smoke and VDB collisions. Even with high resolution VDB I get the stepping effect you see on the image, when the collision surface has inclination. Anyone has any solution or any tips? Thank you.
  24. Hi guys, I'm doing a dust simulation using smokesolver. I used a VDB from polygon sop and created a SDF version of my deforming, collapsing building for collision object (volume sample). The problem is the SDF collision just clears the smoke when they are colliding and doesn't change the flow at all. I tried to create a sample hip but it seems correct with a simple box. Did anyone have the same experience before? and I should mention that my SDF resolution is enough and. Thanks for noticing
  25. Hello everyone ! I'm trying to get an object impact sand. To achieve this kind of effect I planned to create a setup based on this great idea: https://vimeo.com/155198661 Here is what I have so far: Unfortunately I lack the maths to go further. What I need is to spread my velocity vectors outward from the collision mesh and also to remove any vectors that are "BEHIND" the motion. I was wondering if there was a way to ramp down the density using a volume VOP and the BB attribute but no luck so far, or find a way to emit more grain at the front, avoid a constant emission within the volume. Do you guys have any suggestions ? Cheers ! sand.avi collide_setup_01.hipnc