Neon Junkyard Posted December 5, 2014 Share Posted December 5, 2014 Hey guys, I have an alembic file of an animated deforming creature from maya. I am converting it into a VDB volume and applying noise via vop sop. I created a rest.x rest.y rest.z volume to compute the volume rest fields for animation. Now the problem is, after I create these volume rest fields I need to then deform the volume rest fields to match the alembic animation so my rest field will deform along with the geometry and the noise will stick to it without any slipping At the most basic level I can manually keyframe a xform sop, but the noise slips when there is deformation; i.e. this only works with translation or rotation So is there any way to somehow transfer the deformation of the alembic animation over to the volume? I tried transferring density to points, deforming via lattice and then transferring back, but this caused a huge loss of detail/unpredictable results. I also tried transferring volume attributes, along with a thousand other things, with no luck. I posted an example file. Thanks! volume_deform.rar Quote Link to comment Share on other sites More sharing options...
loopyllama Posted December 5, 2014 Share Posted December 5, 2014 well, I cheated. I took your alembic geo and did a standard rest. then I did a "Volume From Attrib" and fed the rest attribute into a rest vector volume, and merged that into your cloud volume. the result is that the noise sticks to transforms and animations but the volume is hollow. I am only creating a rest on the points of the mesh. maybe you can fill in the center, or scatter points internally, or something clever. volume_deform_2.rar Quote Link to comment Share on other sites More sharing options...
Neon Junkyard Posted December 6, 2014 Author Share Posted December 6, 2014 Thanks loopyllama for your response. While that does work in theory, the scene I provided is an extremely watered down version of my production file and when that technique is applied to mine the rest fields go berserk. It seems VDB's do respect a rest SOP when using a VDB vector merge to create a VDB rest field vec3. However when applied it completely changes the noise output when compared to using regular position. My noise is being displaced outward, so the rest field is, I guess, sucking the noise back to the original position of the geo instead of respecting the displaced position, like it would if using a regular volume grid as rest. Still haven't figured out a solution Quote Link to comment Share on other sites More sharing options...
anthonymcgrath Posted June 22, 2016 Share Posted June 22, 2016 hi i'm fairly new to houdini and finding the same issues myself - did you discover a solution to this or is there a way around it ? I'd love to know Quote Link to comment Share on other sites More sharing options...
Federico Posted June 22, 2016 Share Posted June 22, 2016 Hi antony, you can try the "deforming object" tool in the rigid bodies shelf. Quote Link to comment Share on other sites More sharing options...
anthonymcgrath Posted June 24, 2016 Share Posted June 24, 2016 hmmm tried that but tbh it just creates an auto dop network with nothing much different from the usual from what i can see ? I dont need it to be dynamic i dont think i just want the volume fog to deform with the alembic character animation really so its a 3d fog as such as created in the op's file but it deforms with the character Quote Link to comment Share on other sites More sharing options...
anthonymcgrath Posted June 24, 2016 Share Posted June 24, 2016 tried pointdeform node but doesn't seem to work - that said i'm prob doing it wrong Quote Link to comment Share on other sites More sharing options...
Neon Junkyard Posted July 5, 2016 Author Share Posted July 5, 2016 I made a separate post with the solution to this as it has been asked in a few different threads, if anyone is still looking for a solution to this check it out here- Quote Link to comment Share on other sites More sharing options...
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