colortwist
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Bi-directional thigh collider in Houdini
🕑 Added 2021-03-28 15:01:00 +0000 UTCStill here, still working on stuff. Figured I might as well post this because it's been a while since I've posted anything on the technical front.
Aaaanyways...
Been playing around with some VEX stuff in Houdini recently. One of the things that's always bothered me about collisions in C4D was that the collision deformer didn't support any kind of multi-object collision- that is to say, you could only collide one object against some other impenetrable mesh, and never two objects together at the same time. It was sometimes possible to hack around this with proxy meshes and a bunch of other trickery, but performance was never that great nor was it very stable.
So I wanted to see if I could come up with something similar in Houdini, which turned out to be a lot easier than I thought. It could probably still use some optimization, but the basic idea works pretty well.
This will probably land up handling the thigh collision on my new models, since I want to try and incorporate something into these characters to prevent the legs from clipping together so badly (especially when inflated). It's really hard to get a good hourglass profile shot without crossing the legs a bit, but that quickly becomes nearly impossible if you're dealing with super thick thighs- so something else is needed to push the thighs apart and make them look like they're rubbing together rather than blatently clipping through themselves. This will likely land up being the system I use to try and make that happen.
Comments
Yeah, it's exactly that. Instead of having to manually sculpt things so that they're not clipping together (ie, the geometry is intersecting itself), something like this will handle all that for you so you can just focus on the posing and know that the mesh will automatically avoid any clipping issues wherever it can.
Liquid Potato
Oooooh, neat! So, forgive my naivety, but I'm curious: So like, the collision mesh kinda smooshes out that part of the model when you pose em to make it look like the bits are squishing together automatically, no extra manual tweaks needed? Would this then work for, say, two separate character models pressing against each other to get a sort of 'mutual squish' between them? Anyways, cool stuff, always intrigued by the technical aspect, behind the scenes n all.
