Pretty new to blender so forgive me if I’m doing something stupid. I’m using base blender 2.8 and I am trying to rig a character with with a bvh from a capture suit. However the models i have are in T pose and the rest pose of the bvh are legs spread too. so when i edit the pose to fit the rig it ruins the animation making the legs be crossed. I’ve also tried changing the rest pose but it doesnt seem to fix the issue.
Is there a way to rig it to a T pose AND keep the data correct?
I’ve linked the video to help explain it.
Yeah, problem is, it’s very tricky to change the default pose of an armature which is already animated.
But anyway, if you need to change it, don’t do it in edit mode
After positionning your mesh, go to Pose Mode on the Armature. Then set a pose which is Ok. Then go Pose → Apply → Apply Pose as Rest Pose
Wouldn’t use the bvh import armature for immediate rigging purposes at all, as far as I understand it they’re not meant to be used immediately as a character’s rig (?).
You can’t rely on bone Y-axis rotations to always have reasonable values, in particular knee and elbow joints which should only rotate around one axis might end up broken. At least that was the issue I run into when providing last-minute support for a project years ago, they did it the way you have in mind now and had to find out that arbitrary limb twists can’t be fixed by shape keys.
I’d recommend to use a dedicated armature which “knows” about proper limb range of motion. You can use constraints pointing to the bhv skeleton’s appropriate bones to “transfer” the animation to that armature. The Y-axis rotation issue can be fixed that way too, use IK chains for arms and legs, restrict IK degrees of freedom for forearm and shin, and IK-constrain the chains to the bvh skeleton’s forearms, poles could be copy-location’ed on bvh skeleton elbows and knees, that forces the chains into proper bending without breaking the joints.
Sometimes this works. Open the bvh in bvhacker. It has a function you can add a T-pose to the first frame of the bvh. Save the bvh and import like you did before.
I also had a problem with the leggs crossing. Everything else seemed to be working fine. Fixed it by only adjusting the Z-rotation of Left- and RightUpLeg in the Graph Editor. In my case I had to drag the whole curve up or down 20 along Y. Explained in somewhat more detail here: https://www.youtube.com/watch?v=9ou6Q9-gsyA
I guess it is not mathematically correct, but after 3 hours of searching for a solution, I will take it!
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