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Showing results for tags 'vel'.
Found 19 results
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Hello everyone, I'm working on a very specific earth/ground blast. Inorder to keep the max control I decided to create pre sim wich would be used as a source for the main simulation later. Or I'm going to build it in directly and blend it with a pyro solver over time. Anyways, the goal of my setup is to create blast trails wich have an outward momentum. But having a vel field wich pushes density outward causes mushroom with a pyro solver because of the nature of divergence correction. A custom solution should help me out but I'm stuck cause the vel field is not expending but keeps clipping to the density source region. Even vel is advecting vel. There is already a post which seem to had a simular issue but it didn't work for me. advecting velocity by itself. Any ideas? vel_clipping_issue.hip
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Hey, I'm starting this thread because I am working on a very large and calm river at the moment, so I have to invect a stable and constant velocity, without too much craziness. - volume source "add" just keeps getting stronger and stronger, even with a very low value it will keep powering up during 400 frames and never gets to a stable speed. - volume source "copy" is indeed more stable but more hectic, it gets crazy faster - v attribute in the flip source does the opposite of "add" volume source. It starts of powerful but after a few hundreds frames it ends up slowing down. Am I using those volumes the wrong way ? Additionally when I go for a calm river I always end up with a fluid surface that has intense and fast flickering, I am trying all settings when I do the meshing but I notice that it does get worse with using v attribute in the flip source.
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Hey magicians, I'm trying to build a velocity field to advect some VDBs from a shape to another, main Issue im having is that on the center, the velocity is too light, tried multiplying but stills cuts at some point, here are some images to illustrate: Any help would be great! Thank you!
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Hi! I have a question about VDB vel. Let's say there is a a "cached VDB" sdf and vel where vel exists only around surface. Then I try to fill out vel inside. If you have a good idea, let me know, thanks!! (sorry, I uploaded the same pic by mistake, and cannot get rid of that...)
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There's vel volume, but I can't see it with vdb analysis. Why not...? help me!
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I'm wondering why this custom velocity is not work? I have tried various methods, but I'm not sure how....
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So, I am trying to advect some particles around a torus with a 'volume velocity from surface', thing is, once they get out of range of the torus they just kinda stay there. So I am trying to add another velocity field to push them back, however I have gotten awfully stuck on this. In the example I have a torus with velocity and a box with all velocities pointing inwards, so how do I best combine these two? Also Happy New Year to all! vel_test-01.hiplc
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Hi; In case if we need to create an attribute for a simulation, what is right name for velocity attribute for Pyro, Fluid, Particles, RBD, simulation? "v" or "vel"? Thanks.
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Hello ! In order to setup my different Disturbances and Turbulences inside of a smoke simulation, I'd like to know what range of velocity I'm dealing with. How would you guys do that ? If you have the proper method to do that just ignore what's under. The sim is already cached (density, vel, rest, rest2). What I'm doing for now : When looking at the node info there is vel.x, vel.y and vel.z. I don't understand why but I've read that these are scalar values and has to do with how Houdini works so why not. I don't know how to inspect this volume further than that since it's a volume the Geometry Spreadsheet doesn't display anything. And when I apply a VolumeSlice I get 10 different vel attributes per point. vel[4] matches vel[7], vel[5] matches vel[8] and vel[6] matches vel[9]. But not the rest of the values. This is very confusing to me.
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I'm trying to imitate the motion of rocks falling on dirt. Since the RBD Solver seems to give me more accurate and realistic looking results over the Bullet Solver, I decided to go with that method using RBD Fractured Object. When I first had my scene setup with Bullet, I was able to use a little VEX in the SOP Solve to artificially reduce velocities as rocks fell below a certain Y value. It seems like that setup isn't compatible with my RBD setup, so I was wondering what would I need to do to get it working? In addition, how can I write an expression that would tell the solver to reduce the velocities of the objects by half and double their weight each time they impact the ground? Any tips would be greatly appreciated. Thank you! RBDTest_001.hiplc
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Hey guys, I'm growing some objects using volumes (scene is attached) and I'd like to have motion blur on the moving/growing areas. I do have some velocity on the volume, in order to control it's growing direction, but i have no idea on how to transfer it to the mesh itself. here's how the setup looks like: Thx Volume.Growth.Velocity.v1a.hiplc
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Hi, I am creating a "velCombined" attribute which I would like to print as a float value which I would then be able to copy/paste relative references. I was not able to find out how to do specifically that. Please help Thanks
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hey, I want some curl noise to affect my flip particles which works. I also want only the actual vel streams to affect the sim. Unfortunately everywhere the volume box is present flip gets affected. An easy solution for this? Only happens when I add noise to the vel field. untitled.hip
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Hey guys! Need your help. I create some smoke going on top and decide add some custom vel field. I follow this masterclass but after sim I got this strange square look on edges of the smoke... Any suggestions?
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Hi, I just did this test with a grain sim meshed with vdb exported to max rendered with vray. I added the motion blur in comp cause I could n't figure out how to transfer the vel attribute from the grain sim to the vdb. I saw some info about how to transfer an object velocity to vdb volume but it doesn't seem to work the same way with a grain sim. Can anyone give me some tips about how to do that?
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Hi,guys. Recently, i want built a tornado like pyro, a huge storm. The image come form man of steel,Alexander Lombardi Fx Reel ,https://vimeo.com/84196857 Before it , i have to list a better way to drive smoke rotate. So there is a simple test which include a tube source and a vortex force, i'm just add the vortex to the vel filed, after a while, you can see the smoke looks like a dish. I don't know if it was a nature shape, most like the air in middle was all been push out, so the air on top and bottom be attract in. So i have to find a way to disturbance to vel, first i want do it by pressure, high pressure air flow to low pressure lead to a wind, is it right? So i inject a custom pressure field, i not clear with how pressure working in pyro, i can export the pressure filed or modify it, but the pyro simulate not change at all, even i set the pressure to 0. Second way i modify the vel field directly, at the few frame of beginning, the vel field was direct to middle soon, i built a gradient field of the vel.y , if it great a value, then slow down the vel, it clamp the vel totally, although the smoke not rotate crazy, but it also lose the nature detail. I will keep optimize the second way. If anyone lead me a better way to built the tornado storm, or explain me how pressure working will be great. Thanks. pyro_pressure.hip
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I am doing some test and thinking about to use the fluid to get the overall motion but wanna add some control to each point. My problem is: I don't wanna any points have dramatic velocity direction change from frame to frame. My question is: Is there a way I can fetch previous velocityl vector in the flip sim, so that I can use it to force current vel only change withing certain rang.
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Hi, Guys. I have just begin to learn volumevop. I bulit a vel volume form attribute N. What i want to do is modify the vel value in volumevop. But how to import the vel attribute to volumevop. I try to use Primitive Attribute, or Get Attribute, it seems not work at all. Any help will be great! Thanks! volume_vel_multiply.hip
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I have a smoke sim. I want to reduce velocity in the area inside of small box (like in pic). I want to have opportunity to fill this area with custom velocity. Thanks.
