/3/ - 3DCG

>>980898
So look how all my horizontal edge loops stay horizontal and all my vertical loops stay vertical. This lets the butt meat open up and close like an accordian. Your butt is very small in comparison and the loss of volume isnt as big of a deal, but here I have an extra joint in the same location as the femur joint which is driving the motion of the verts on the parts of the butt between the pelvis/tailbone and the upper thigh.
So this riddle about the "pelvic bone". You have 2 joints here fighting for control over all these verts. you hip joint and the femur joint. There are parts of the body where skin and tendons are thoroughly affixed onto the bones underneath them. The part of the pelvis most relevant is the "ilium" and the "coccyx" (google em). Imagine (or model) an actual pelvis under your mesh. The verts contacting these parts of the bone should have a 100% envelopment by the hip joint. So they do not move at all when the femur moves. All that tissue is then tied into the big bump on the outside of the femur called the "great trochanter". When you move your leg around all those muscles and fat get pulled between the pelvis and the femur.
For the most part your rig is already doing this fairly well and unless the camera is going to be focussing on her ass cheecks while she does gymnastic moves it won't be an issue. Those 100% pelvis verts are important up around the hips to keep her from looking like she's made of rubber.

>>951384
it doesnt look like the butt is responding to tension or compression at all. multuple bones is the way to go. It should be the foundation. On top of that you add soft body dynamics.

>>938917
the bigger the butt the bigger the problems.
If you want the crotch and cheeks to deform properly they need the same tubular topology as the leg or arm. Problem is there's a big inflation point on one side and a tiny pinch point on the other. Lots of edge loops close together will make rigging and animating very difficult. Letting the cheek have few edge loops quickly stops looking good.
MY answer is to go ahead and have a ton of crotch loops. They're a pain but it's possible to envelope them and compensate for daformation problems with blendshapes. There's nothing you can do if there are too few loops on the cheek side though. You'll just have a faceted ass no matter what.
It's possible to collapse the loops as they converge into the crotch but I think the poles you end up making as a result are worse than ultra dense geometry.

corrective blend shapes are the solution which will work 100% of the time in all cases and look 100% perfect. Because you will need to make the perfect blendshape for every single use case. Every other solution is primarily designed to avoid that work, but will always have some limitation which can only be cured with, you guessed it, a blend shape.
In pic related I have this giant ass which loses a ton of volume. I have added an intermediate joint between the hip and the femur which bares some of the influence on the butt. It's reduced the reduction in volume by like 75%. If I wanted it better I could add more intermediary joints and I'll be experimenting with "flying joints" which will sit close to where the geometry actually is to save volume, but it will never work 100% and there are orientations where the solution doesnt work at all. It'll be a decision I make if I do blend shapes, blend shapes + some alternative, or some alternative + just accepting it'll look bad sometimes.

>>736917
yes but for real time rendering it's not feasible. Vertex animations are way more costly. Additionally, adding an extra control joint is very easy and it works.