I accidently put the elbow as the source in the second rotation constraint. That is wrong. It should be the arm. Playlist with more tutorials: • VRChat Tutorials / airpaca
This might be the best tutorial I've seen on how to do this! I like that it shows the steps to do it manually rather than having tools generate the bones. Thank you so much!! 👏✨
@@Airbee Exactly! I'm in the process of making a selfie avatar of myself for either streaming or VRChat, everything's from scratch so far and I'd like to keep it that way. Thank you again!
thank youu ive always just been trying my best to weight paint it to look as good as possible, but for some models it will just look bad without twist bones no matter what
Good Tutorial. What i also learned is, were that weight paint gradient tool is. That will save me so much time in the future. I always worked around with the blur tool instead. x) I saw someone do it before, but the had shortcuts for it, so i never saw what they actualy selected.
Thanks :) Yeah i really like using the gradient tool, its super useful. As for leg twist bones (youtube still shows me your comment pre-edit in notifications :p), personally i've never heard of them or seen them. You can't really rotate your knee irl and the IK also doesnt really do it to your avatar so i don't think you'd need them anywhere there. I have however heard about something like "corrective bones" or something like that... For example for the hip, when you're doing a split with your legs. I was trying to find some information to that aswell but i didn't really find much and didn't bother messing around much further on my own. I can imagine that you add some bones to each side of the hip and add weight paint to them, and then make these hip bones only rotate with the leg to a certain extent with a rotation constraint (for example 60%). This limited rotation together with a different point its rotating around could probably make a couple of leg poses look a lot smoother than just with hip/leg/leg bones.
@@Airbee oh i see haha i edited it, because it is the same setup with the constraints as the arms. I was just being dumb. If they are actualy used i dont know myself, but most popular base bodys i have seen have them aswell. So i thought it would be a good idea to make them for my own body base. If not, thats fine. maybe people have other uses for them outside from vrchat.
Rotation constraints it how I was thinking I was going to have to do the twist bone set up for the avatar I am making, but was hoping there was another method, as the avatar has quite a few bones in it that require the use of rotation constraints, and excessive constraint usage supposedly can cause performance issues, but soo far I have seen no valid alternative options, except those that require installing additional plugins to unity that almost certainly are not compatible with any of the common VR platforms (Namely VRC and ChilloutVR), so it's looking like rotation constraints are the only realistically viable option.
If i'm editing an avatar to include twistbones - and already have a scene set up in Unity, Is there a way to overwrite the FBX and maintain the scene? Or will I have to recreate it? The issue I'm having is overwriting the original FBX causes the body of my avatar to disappear completely from the scene, even though I can drag & drop it into the scene otherwise. So it's not that it can't render, it's just unable to be incorporated into the scene for some reason? Thanks!
Sadly this doesn't work for me. When the arm is bent it keeps the first (twist1) bone in place and only bends the second (twist2) instead of the "elbow" in VRChat. The rig has none of the twist bones set in the fbx settings and I'm a little lost why this happens.
Why is the rotation constraint needed? Just curious because I genuinely dont know. I know constraints aren't quest compatible and I havent seen other avatars with twist bones need constraints
VRChat's IK only controls/rotates the upper and the lower arm as a whole, to 100%. But in a real arm there is some kind of transition, where the parts close to the elbow of the lower arm barely rotates when you rotate your wrist. And on the part close to the wrist it should rotate a lot, almost exactly copy the wrist rotation. Rotation constraints on the twist bones we created allow you to say "Ok, this part of the lower arm only rotates ~15% of what VRChat IK does. And this other part of the lower arm rotates ~80% of what VRChat IK does." This results in a way smoother lower arm twist. If you have twist bones and want to actually use them for a smoother twist you do need constraints :D But i think a lot of avatars have twist bones, but simply ignore them and dont utliize them, therefore no constraints
Why do you say that the original forearm vertex group is unneeded once twist bones are set? How will the forearm move without it? I feel like I'm missing something here. edit: oh duh, the twist bones are parented to it so they do movement and rotation. Nevermind.
I wish you had used normal names for your bones when you made this or at least showed it in pose mode before moving past blender. When you say parent to elbow what do you mean? There ins't anything called elbow, do you mean your upper or lower arm bone? And what about your hand and if you have other pieces on the arm? Do you need to add those to the new bone parent? Once you rename the vertex group it breaks the old bone so this method doesnt work without more steps you didnt mention.
