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Showing results for tags 'velocity'.
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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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My popular Custom Velocity Forces class just got UPGRADED! Previous students enrolled should already see the updates now. For new students you can enroll here: Learn more Thanks for the all the support everyone! Updated promo video for the class:
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Hey everyone, I'm working on an Houdini FX project and I'm trying to create a custom velocity for my particle system. Specifically, I want my particles to travel from one point to another along the edge network. I've tried a few things, but I'm not quite getting the results I'm looking for. Has anyone else tackled a similar problem before or have any advice on how to achieve this effect? Any suggestions or resources would be greatly appreciated! Thanks in advance. Here is an exemple of the edge network :
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Hello, I am studying muscle system, and prepared a setup with a cycle inplace walk animation for my creature. That way, everyhting worked fine. Next step i tried switching the old animation with a new one, running in space, much faster than before. The result now appears completely broken, seems like muscles cannot follow the bones promptly, they're remaining behind the bones and intersecting each other they are not able to deintersect. I just tried to: • increase the stiffness for muscle-to-bones and muscle-to-muscle constraints, in Properties Sop • remove all damping values, in Properties Sop • increase substep, in Solver • increase constraint iterations, in Solver • added velocity stiffness factor (fresh new property in 19.5.409), in Properties Sop • added velocity blend, in Properties Sop • enabled velocity blending, in Solver • increased velocity damping, in Solver None of them worked or gave acceptable results. Any tips on how can i fix it? Thanks Update: speeding the solver x2 faster seems to give better results, although still not perfect. Not sure this is the right path anyway.
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I always have problems with motion blur for water surface mesh, One time I fixed that problem but I forgot that. as you can see I used a trail SOP to produce velocity for the mesh but the trail SOP creates velocity per point and that's why the motion blur is odd. How can I create proper motion blur for water surface mesh?
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Hi, I'm trying to render out some simple points (rendered as spheres) with Arnold in Solaris. Looking at the Arnold documentation, this should be a simple one-step solution but so far I had no success. There's only a single checkbox under the Geometry SOP and no other options than that. I'm able to get the camera blur however. Any input would be appreciated. Thank you. -
Hello ! I'm actually Working on a project of underwater Bubbles using the pyrosolver. I'm using a first sim for creating a velocity field (mixing turbulence and an animated 3dmodel) and for the second sim i'm creating a smoke that I'want it to be advected by the first one (using the velocity of the first pyro sim) but I don't find the good way to do that, this is the vel from the first Sim and this is the second whant that need to get de vel from the first one. I don't know how to use the vel from the first sim and if I have to put something in "velocity update" or "advection" . Any Idea please ? thanks =)
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Hey folks, proud to present LYNX Tools, a collection of production proven open source tools to accelerate your workflows! All mentioned tools are free to download via the links below and are licensed with a full HoudiniFX license. All Houdini Assets have complete Houdini native documentation available. Repository: https://github.com/LucaScheller/VFX-LYNX Lastest stable release: https://github.com/LucaScheller/VFX-LYNX/releases Please give them a test drive, so we can improve them further Roadmap | https://github.com/LucaScheller/VFX-LYNX/projects/1 So far there are three tools: LYNX_force_general | Tweak your sims with this all purpose & intuitive force field. Built to mimic force fields in other DCC applications, but with support for more features and a natural Houdini user experience. https://www.lucascheller.de/vfx/2019/03/24/vfx-lynx-houdini-force-general-asset/ LYNX_fabric | Create fabric/weave patterns with ease. Perfect for creating that holiday sweater you never wanted. https://www.lucascheller.de/vfx/2019/03/16/vfx-lynx-houdini-fabric-asset/ LYNX_velocity | Get control of your velocities via an intuitive UI or groom them for absolute fine tuned control. https://www.lucascheller.de/vfx/2018/11/01/vfx-lynx-houdini-velocity-asset/ More info on my website, including full release logs: https://www.lucascheller.de/blog/ Houdini User Group Munich Presentation: https://vimeo.com/334887452
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Hi guys, I'm really struggling with what seems to be a rather easy setup: Covering a collider object in smoke and at some point suck in all the smoke through various holes. Negative divergence seemed the way to go however it's completely ignoring the collision (see attached flipbooks) Any help would be highly appreciated. Thank you! smoke_negative_divergence.mp4 smoke_base.mp4 smoke_suction_fail.hiplc
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Hello! I am building a flocking sim, and I am trying to get the turn information to propagate across the flock like a wave. I am using particles as "birds", so each particle represents a bird. I am trying to figure out how to use a ripple solver that uses a volume to broadcast the velocity information of each particle at each time step out to the rest of the flock, so that the turn information moves through the flock in a wave-like fashion. LMK if that makes sense and if you have any suggestions! Right now I just don't know how to read the velocity information of a particle into the ripple solver, and then ripple that information out to the other particles. Thanks!
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Hello everyone... I have a problem with an RBD packed object inheriting velocity. In the file, I have the attribute active being set by another object, but the velocity doesn't kick in at all. The velocity works if I remove the point wrangle setting active to 0 and remove the sop solver. If I try a pop vop or a geo vop, there's some weird velocity behavior that happens. If I tick on override attribute, the velocity takes off big time and doesn't appear that gravity takes hold. All I'm looking for is initial velocity once the pieces become active. I saw a few threads on the side fx forums and this forum, but nothing I saw seems to be working. Any thoughts? test_active_velocity.hipnc
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I am happy to announce that I'll be joining a host of talented Houdini teachers, like: Debra Isaac Kate Xagoraris Beck Selmes Christopher Rutledge Justin Dykhouse Jeffy Mathew Philip Nicholas Ralabate You can learn more about my Velocity Forces class here: https://www.houdini.school/courses/hs-204-forces-building-custom-velocity-setups Teaser video for my Velocity Forces live class: https://vimeo.com/577928177
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Hello guys, i'm making a explosion scene. The bomb was applied to only two frames and the wheels continued to be affected. Is there any way to stop the wheel? Just in case, I tried using VEX, but it didn't work. I tried adjusting the speed in RBD Configure. but it didn't work. Is there any way to stop that Velocity? ex_test_5.mov
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Hi peeps, I'm currently working on a project where I need to emerge a large object (3.5m) from a fluid surface. Everything works fine in my scene but for one thing I seem not to get in control of.. The issue I'm facing is that when the large object emerges from the surface it creates some kind of suction between the face of the object and the water surface. I know this is how fluids will work in real life but for creative purposes I need to get rid of this. When I go to my collision object and turn the velocity scale down I get rid of this suction velocity but this also has a lot of influence on the rest of my sim. Does some of you maybe have any tips on how I can direct this part of the simulation better? Any help would be amazing. Attached to this post is an image where I try to visualize my problem. The green arrows indicate the direction and movement of the large block. The red outline is the issue I'm facing. Also I've attached a Hip file. This is a re-creation of the problem (I cant share my actual file). Thanks in advance! example_scene.hip
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EDIT : Forget this topic. I made a mistake in my node tree. Hi dear, I'm wondering something about velocity. On my node tree, i have creating a group of point with some velocity > 0. Then I have "resample" the curve. And some of the new points, close to the group of point have a velocity transfer. And I can't see where this is coming from. They should have a 0 velocity. Even if i create an other group with a v@v={0,0,0}; the transfer is still present. Any help ? Thanks
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hey! I'm trying to emit a flip fluid with some velocity, I can add a generic velocity in world space but in my case I want to add velocity along the normal of the object sourcing...just can't figured it out yet
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Hey all I have some low-ish resolution VDB dust clouds created in C4D with the TurbulenceFD plugin. These contain velocity channels. So far, I'm just not satisfied with the overall detail. What I've done to try and increase detail is convert the VDBs to Volumes, Volume Resample them, then use Volume Velocity to add some curl noise. It's looks OK, but by no means what you would call a true Up-res, that uses existing velocity channels to increase detail in turbulent areas... So that's the question really. How do I take a pre-calculated VDB (not dynamic at all) and give it a high-res makeover? Any pointers would be appreciated. Please be aware that the overall motion has been signed off, so all that I should be changing at this point is detail. I would just do the Up-res in TurbulenceFD, but it's buggy as hell and wont work. Every day I get closer to ditching C4D entirely. Thanks!
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Hey guys! I need to kill particles that have little/no movement. The trouble with killing by velocity is the particles that are moving, are varying in the axis they're moving in so I can't just kill @P.y ? Any suggestions? Is it maybe possible to get each a particles speed of some sort?
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Hello, I am thinking that I've forgot the vex code for giving birthed particles some velocity... I have used this code to give some velocities to the particles... @N = @N @v = @N but now I am back at Houdini and I have tried it again and somehow it isn't working anymore... And how should I start to achieve the result like in the video? I am trying to get the main explosion burst on the torus so that I can use the same way to my already modeled falcon 9. There is a "ring" of smoke which I like to replicate to my torus... The air explosion from 0:18 to 0:22 I would be very glad if someone could help me Thanks in advance (
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Hi everyone, I have a velocity volume working well to advect a vellum sim, by pulling the objects towards the normals of an object. However I'd like to remove all velocity values from within the object, so that once they've been pulled in and "captured", that they can then move freely within the shape of that object. The object is not being fed into the vellum sim for collisions. Is it a matter of doing something like, multiplying the velocity by the inverse of the density? I tried this but couldn't quite get it right, I'm not sure if I'm missing something. Thanks in advance for any help! VelocityRemoveInside_Test.hiplc
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Hello people. I have created points and with my Vex code I am giving them velocity to "attack" an object, but right now my points are going in a straight line to an object. I wanted to ask if there is a way how I could make my points travel with curved velocity (like missiles in my reference photo are travelling)? I know there is POP Curve force, but I would like to find a way to do it in POP Wrangle. mplay.mp4
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Hi! I'm pretty new to houdini's flip fluids and I'm stuck with something. I have a flip fluid liquid simulation with boundary layer for river like effect. I've setup a boundary velocity field to create the river flow. Now that I'm trying to add some pop wind in order to add turbulences, it appears that it overrides the boundary velocity effect. SoI'm looking for a way to blend those two effects. Any ideas ? Thanks.
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Hi; I would like to add some velocity to particles from a volume (smoke), so I tried to use "POP Attribute from volume", but it doesn't work. How can I fix it? Actually, "POP advect from volume" works, but I would like to ADD/Multiply the velocity to particles, not advect them. Thanks for helping. POP_Attribute_from_Volume.hip
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Hello, I asked the exact same question in the official houdini forum and got no answer yet, hope that's no problem I'm trying to make an object follow a path created from points (positions imported from an external file) with a velocity based on the distance of subsequent points. I used the method of creating a line from the points and constrain the object to it. Then I calculated the distance between subsequent points in a wrangle inside the path-geometry node and stored it as a velocity attribute. My idea was to somehow “channel” the velocity to the position parameter of the constraint path, but I don't know how to do that. I'm new to houdini and therefore assume there is a much better way to do all of this. Maybe one can create an entire animation path with the velocity information directly from the imported point positions. Reading several documentations about velocity attributes did not help… Thanks, Lukas positions.csv simple_pendulum.hipnc
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Hi guys! Recently I was asking for some advice on how to deform spherical parts of volume into different shapes (in my case skulls). And here is the best reply I've got: "You need a dop I/O node - target your dop network and then point it to your smoke object. Add an import field with the little plus button and import the field named "Pressure". This value is very small but if you use volume visualize nodes or volume vops you can fit the values to pull out the pressure range where these mushroom shapes occur. Once you know the range (usually somewhere around 0.02 to 0.00 for these shapes) you now have the correct mask range. You can now set "Pressure" as the control field in your disturbance tab on the pyro solver. Just make sure you use the correct range, then you can dial the strength of your disturbance applied in only the areas highlighted previously in your volume visualizer. One thing to note - if you want to identify them each you're going to need a sop solver. Once you have the pressure field isolated, you can convert the vdb to poly and use connectivity to seperate them out and then pack them to get a centroid for the specific mushroom. But you're going to want to blend the point position of that centroid over time as it may jitter or pop in and out of existence depending on the tightness of your isolation range. Once those points have a history they'll have velocity and direction you can use to orient your custom field that warps it into a skull or whatever." However, I'm stuck on the last step where I have to setup sop solver and feed the output back in a sim. I would be very grateful for any advice or more detailed instructions on how to set the last part up P.S. I've attached a basic setup file in case if needed sklsmk_test.hipnc geo_02.0001.bgeo.sc
