Hey all. I’m following along with Michael Pavlovich’s fabric Youtube videos for ZBrush 2021 Dynamic cloth.
One big difference between his results and mine: I’m getting a ton of what I can only call “Voxel static” when I use collision volumes, enough that it makes the fabric simulation practically useless. It’s a series of squares like lines on a topographic map that do not exist in the underlying mesh, but that immediately appear as soon as I try to run a simulation or use cloth hook with Collision Volumes turned on, almost as though the voxel computations that ZBrush uses for many things (like Dynamesh for example) are being embossed into the surface of my mesh. I’m an experienced user, and have monkeyed with a lot of settings, but nothing seems to get the squares to stop appearing. The squares are made up of the mesh of the dress, but like they’re being pushed straight in from the planes of a surrounding cube rather than being allowed to rotate to match the underlying collision volume.
Any insights or ideas on how to make this stop? At this point it’s more practical to just sculpt the fabric by hand because the smoothing required to remove the texture destroys most of the simulation anyway.
Hello @Mighty_Thor
Out of curiosity, how large is your mesh? This looks like the sort of surface distortion that can happen when a mesh is drastically oversized in the ZBrush worldspace. ZBrush requires a mesh to have a Tool > Geometry > Size > XYZ size in the vicinity of 2 for best results. Meshes that are much larger or smaller than this value may experience odd behavior with many tools in Zbrush. This video explains some of the reasons why.
Otherwise, this is a new tool, and experience with it in the community is limited at this point. I don’t have a lot of experience yet to draw on. I will say that the documentation takes pains to specify that the Dynamics work best with lower resolution meshes, both for performance reasons, and also how sensitive the mesh the mesh will be to distortion. You may have better results if you drop the resolution of your mesh a bit, then rely on subdivision or Dynamic subdivision to smooth it out.
Finally, try increasing the value of the Resolution slider in the Dynamics palette. The lower this value is, the “blockier” the results will be. Reduce the firmness of the cloth for finer wrinkles.
Let us know if anything here is useful to you.
Good luck!
Thanks for the reply.
The Size is a good thought, it was at like 2.8, but nope, setting it to 2 has no real effect.
I’m using the same resolutions Pavlovich is in his demo, same settings, different results, and various tweaks along those lines don’t change much. The program’s first response on simulation or even first touch with the cloth hook is to generate voxel static all over, not even confined to the areas I’m actually touching with the brush. Again, only while using collision volume.
I get that it’s a new tool, and wasn’t expecting much community experience with it, but at a minimum I assume the devs follow these posts, and this can serve as a sort of bug report if nothing else.
If anyone runs into a similar deal, please let me know.
-Thor
@Mighty_Thor As Jaime mentions increasing the [Dynamics:Resolution] slider for the collision volume will help.
Also it appears that your clothing right now is ~88,000 points? The more resolution your clothing subtool has the more details it will pick up from the collision volume. You can also try ZRemeshing your garment (To reduce the topology) and using Dynamic Subvisions.
Cheers,
-Joseph
Thanks for all the replies- as followup:
Just taking the Resolution to 3200 has no real effect on the phenomenon, good idea to try though.
Remeshing the dress to 22,000 points didn’t stop the phenomenon, but did make it “blurrier” and the lower res is easier to smooth without destroying the work the simulation has done. Still very lumpy/staticy overall.
Remeshing the underlying figure to 26,000 points as well as the previous two fixes still leaves an oatmealy texture to everything, and creates raised artifacts along edgeloops, but is easier still to fix with a quick tap of regular smooth. Smoothcloth cleans it up somewhat in areas that are pulled “taut” but also generates new static within the new folds and “compressed” areas it creates.
Remeshing the dress to 10,000 points mostly removes the issue.
Remeshing the dress to 5,000 points eliminates it entirely, and Dynamic SubDiv gets back to the high res detail I was shooting for really quite beautifully.
A SmoothSubDiv setting of 3 was the best compromise between quality and processing speed on my system.
So yes: It is a phenomenon exclusively of higher resolution meshes, and the new system does indeed work best with minimum mesh size + Dynamic SubDiv making up the difference.
So thanks to all, trophy goes to Joseph Drust / Piggyson (no surprise)
SOLVED and thank you all again.
