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Found 102 results

  1. Hello! Normally I always find the answers to any Houdini issue that comes into my way, but this time I decided to finally communicate my current issue! My first question ever in odforce hehe So well... I'm doing my graduation film, and is about a shepherd that transforms sheep wool into clouds for doing rain! After some previous phase of research, we decided to give the wool a "cloudy" look, more than giving clouds a "wooly" look. So I'm using volumes to recreate the sheep wool! Thanks to various threads made by countless users here in odforce, I was able to: *Create interesting noise density values for the VDBs, hence giving a "wooly" look to the volume. I wanted "puffy" looking volumes, so I scattered particles in the sheep mesh, and created VDB out of them. *Transfer spatial transformation data from an alembic animated mesh to a volume, this way helping me to maintain the overall noise that will have otherwise been calculated at each frame if I moved the mesh I used for the VDB creation directly. *Deform the noised volume through a volume lattice technique by Juraj Tomori and Matt Estela (I'm enormously grateful for having shared their hip files!!! They saved my life). The volume will keep its noise while being deformed by box, itself deformed by an edit or a bend node. Up until now! Everything is going well! The only issue I have is.... How can I assign the point cache information of an animated lattice in Maya to a box with the same dimensions and subdivisions in Houdini? I thought that maybe an attribute transfer I could transfer the P data.. But I don't know if I need some vex to grab the position of every point in the lattice an assign them to a new matrix... I have no idea.. But knowing how to do this will be excelent! This way any lattice deformations the animators will do in Maya will be directly fetched to the box in Houdini! Any ideas?
  2. I can't figure out how to get the output created by the "Sky Rig" shelf tool from the Cloud FX shelf to render with Redshift. I have no similar issue with the volume created by the "Cloud Rig" tool, although both seem to me like they create a VDB volume with a channel called "density" (which is what I've tried to render in Redshift with an "RS Volume" shader, which again works just fine with the kind of volume that "Cloud Rig" creates). What am I missing?
  3. Hi, Can anyone shed some light on how to use the gasBlendDensity microsolver? I haven't seen a working example of it anywhere. Here is an example scene with the fields setup, trying to blend between 2 volumes. gas_diffuse_blend_example.hip Cheers
  4. Hello ! Is there a simple way to transfer velocity attributes from a volume to another ? Or create velocity from scratch ? Thanks !
  5. Delete by Volume

    Hey! I have a sphere, then delete by volume. I have the bounding volume animated. Here is the problem: once the primitive leaves the volume it reappears. How can I keep it permanently deleted, even if the volume leaves that primitive? Thanks delete_volume.hipnc
  6. Just curious if anyone has recreated fStretch or similar a volume preservation method inside Houdini? fStretch - Softimage version - Are there any papers on this sort of thing?
  7. I am adding the uniformvolume material to my geometry to get simple and quick fog. Works like a charm (the green example at the top). Why I get the enable dispmap warning, I do not know - displacement is not enabled. Now, if I plug in some more detailed colour information (bottom sample), the fog disappears completely. What am I doing wrong here? Plugging into the colour input is just one example. It seems this material doesn't like to get any inputs. That can't be right?
  8. Hello, now when I am loading VDB volumes with File SOP it sometime takes some time, especially with big volumes stored on network. I was wondering whether it is possible to load only specified volumes from a VDB file, for example to load only heat, to keep loading times slower. This would save a lot of time in situations where I am blasting all other volumes which I do not need directly after File node. I quickly checked docs and found that it is possible to firstly read the header to find out information about stored VDBs and then to load needed volume (in Reading and modifying a grid section). Any ideas if it is supported right now in Houdini implementation / or if there are any plans to add this? Juraj
  9. Hi all, I have a big pyro simulation where I am clustering the simulation with multiple bounding boxes. The problem I have is that each primitive bounding box has its own density, vel , temperature fields separate. Here is a screenshot of how that looks: Is there a way to combine all those volumes and create one field for each?? Thank you in advance!
  10. Hey guys... So what I'm trying to do here is to make the skull go through the cloud and make it look somewhat natural but I can't get the effect I want I tried it two different ways and both give me crazy advection.... (also I don't know if is just a view port thing or the light, or the sim, but the cloud also looks like id flickering) Anyway I'll attach the file and if anyone can give me some advice on how to do it better or if maybe I'm doing something the wrong way or missing anything I would really appreciate it! Thanks! movingCloud_09.hipnc
  11. In Houdini, can I colorize a volume (either VDB of Houdini volume) based on the voxel location in space? E.g.if I have a cube-shaped volume, can I color its quadrants differently?

    Hello everyone! I have a problem with my alpha, when I render my clouds separately (what i don't render is in matte shading) I end up with weird alphas in compositing. Do some of you have the same problem, or is there something obvious I'm missing? Thank you!
  13. Collision Volume

    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.
  14. Volume Velocity to Mesh?

    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
  15. Volume density from texture?

    Hello magicians, I saw a great image by Lee Griggs the other day and I tried to replicate, here is the original effect He did it with Arnold (i think in maya), by projecting a texture into a volume density, here is some explanation https://support.solidangle.com/pages/viewpage.action?pageId=55710284 I didnt know how to project a texture into density, so I projected a texture, the deleted by color and converted that into vdb > fog, but that way I don't get any depth, any ideas? I've read about a rest field that does something like UV on volumes but cant figure out how Here are my attempts: Hip file attached, Cheers! volnoise3.hip
  16. Hello everybody, Here is my first post so I will present myself in few words. I'm Thomas Renault, FX teacher in ESMA school (France). I'm using Houdini since two years now and I enjoy it more and more everyday. First of all I would like to thanks all the community and SideFx team for feeding us continually with documentation and tutorials. That's the first time I post in odforce because I uselly search and find my answer without requesting anyone. Here is my problem : I tryed to render volume in renderman (21,4) for Houdini (16) with motion blur without sucess. I found this on pixar documentation : https://rmanwiki.pixar.com/display/REN/PxrVolume but no fonctionnal blur at all in houdini... Any advice ?
  17. Y ramp volume vop

    Hey, I am trying to use a volume vop to create a ramp that controls the y density of my volume, so I can have it fade off. If you look at the volume vop in my scene, you can see that it kinda works. There seems to be a problem with the fall off. Any suggestions? clouds4.hiplc
  18. Properly Sourcing Volumes in Pyro

    Hi, How do I properly source a volume I already created, and use that for pyro? I made a cloud using the cloud node, and added some noise. I am trying to use it as a source for my pyro sim to have dynamic clouds. For some reason, at frame 1 there is no density. Then the volume fills up. Shouldn't the first frame just be the cloud already there? I am trying to learn how to source vdb/volumes that I make and use it as a source for pyro. Thanks clouds.hipnc
  19. Does anyone know why volumes have this artifacting that is visible when the grid is behind the volume? You don't really see it if you have something else behind the volume. See photos.
  20. Hi, I am looking for measuring volume by VEX and/or attributeVOP, instead of measureSOP node. Basically I have mega voronoi fracture model. After that, I want to apply for volume calculation with loop node and compile node. Key is that I cannot use hscript expression in measure>center with compile node. That's why I am looking for another method.
  21. Hello! I am trying to create a shader with the Arnold VOP network that is comparable to the ocean volume mantra creates when the ocean toolkit is used. I have Arnold experience, but am having a hard time finding resources related to rendering volumes with Arnold (that are free, I'm a student on a budget). Any help would be appreciated, thank you!
  22. New Quick Pyro Tutorial at CMIVFX

    New quick tutorial explaining basics of Houidni clusterin for Pyro and creating flare effects. https://cmivfx.com/houdini-pyro-and-cluster-simulations
  23. fill mocap volume

    Hi all, I'm working with some mocap meshes that I'm trailing particles over using the 'minpos' technique in POP VOPs. I'm getting a little stuck though, as when i make trails of the particles, these obviously trail behind the mocap as the keep their birth XYZ coords. What I'd like to achieve is that the trails adhere to the surface of the body/geo in the same way that the particles do, so i end up with something like 0:24 > 0:26 of the attached video. Maybe I need to do something within a sop solver? perhaps dop pop is the completely incorrect way to go? Any hints or tips greatly appreciated - I've attached my .hip here should anyone have the time to take a look! Thanks! (hints on filling the volume as-in the video will also be met with rapturous thanks... I'm not even sure where to start with that one.) surface_particles_trail_test.hip
  24. Hi all, Does anyone know how to use the mask input option to smooth a part of the mesh inside the particle fluid surface node? I want to specify with a volume (ie. a bounding box) which part of the mesh to smooth or keep (instead of using the velocity or vorticity mask). I created the volume to mask with (just a box turned to vdb) as a separate OBJ, I am then object merging it and connecting it to the third input of the fluid surface node, then in the filtering tab in mask input I check it and put in the name of the volume. I have tried to do several different things on the volume itself (regular VDB, Fog VFB, etc.) and nothing seems to work or make any difference. When I turn visualize mask on all it shows is nothing is applied to it (ie. all of the surface has 0 smoothing applied to it) How do I properly use this feature and get the node to recognize the mask? Am I going about this the right way? Many thanks, CrownSplash Anim C.hiplc
  25. Hi, everyone. I'm new to Houdini. The question that I bring to you is not mine. I found it in the comments in a tutorial about Houdini volumes and would want to know the answer also. The question is: Is there a way to animate character made of volume and keep its volume noise parameter in a right place? As far as I know the volume noise is based on position, so animating it we are moving character, but noise is stable in its position. We could scatter points inside a volume in the base position and write it down using the attribute, then we could create volume out of particles and use our noise attribute to be read out of points. Is it possible, or I'm just making an unnecessary noise ;-) Best Regards, Tom