In my quest to make boobs I've come up against another snag, one I've not seen before. I'm still doing my standard convert to VDB from polygons, then convert back to polygons, then remesh, etc. The right_boob_remesh_prims group was created from promoting the right_boob_remesh point group, which was made from an Attribute Paint node. However, for some unknown reason, when I give the Vellum Pressure nodes a value above 1, they deflate/shrink instead of expand. I've never encountered this before. If I give them a negative value, they seem to expand but I can't imagine they'll work properly. I assume this is some kind of normals issue, but that doesn't make sense because the model is converted to a volume, then back to polygons. So I would have assumed any normal problems would've been taken care of during that process. I even dropped a Clean node after the convertVDB and before the remesh, and that still didn't fix it.
If I look at the normals, they're also all fine. None of the faces/polygons are coloured like they're back-facing. There's nothing to suggest the faces aren't oriented properly. And yet, a positive Rest Length value in the pressure node still deflates it. I wouldn't even mind this wonkiness, except now I can't figure out why the boob seems to inflate a bit when sways from side to side, as if it were a long breathing in and out.
I'll try another model with my setup to figure out if it's just the base model that's cursed or if it's my setup. I tried this on a couple mannequin models and primitive polygons and got everything to work pretty much how I wanted. If anyone has any immediate ideas for what the bug could be, let me know.
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Anonymous06/09/26(Tue)11:45:38
>>1029401 Why did you move on from using Tetrahedrals? Seems like the more correct choice for flesh from my limited knowledge.
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Anonymous06/09/26(Tue)15:59:32
>>1029409 I may try those again, but the issue I was having was it wasn't deforming the way I want. I need something that keeps it shape, but will squish without too much trouble. With tets (and my admittedly limited testing of them) if you make them too "soft", they don't keep their shape and are too floppy. And if they're too "hard" they don't really deform at all when something presses against them. Even though it's called the "Pressure" constraint, it's really better to think of it like a volume. It could be a balloon filled with gas or water depending on the settings. I was doing some tests with polygon spheres (where they just drop to the ground plane) and got some nice behaviour. They jiggled for about a second and a half and then settled quickly. So there's a bit of bouncing and stretching, but not a cartoonish amount.
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Anonymous06/10/26(Wed)02:41:14
Boob update: while I haven't been able to fix the inverted pressure scaling with this model, I did manage to fix the problem where the boob got bigger/inflated while she swayed from side to side. I just lowered the stretch stiffness of the pressure constraint. I think because it was at max stiffness before, when the model was swaying, it was forcing the volume "somewhere", but because I said the volume wasn't allowed to "go" anywhere, it just stretched everything instead. But now since the volume can move around internally a bit, the inflating boob problem seems to be gone.