Problem with bone rotation

Hello, I’m pretty newbie on Blender. While learning, I modify assets from my games and study how they are made. However, from time to time I meet this issue with animations and I never found any documentation about it, this means I use wrong keywords or it’s something too banal :stuck_out_tongue:

It is pretty hard for me to explain this, so I attach few pictures

This is a rigged body with an already made animation. I want to modify it, so I go in Pose mode, I take one of the bones (in this case a spine bone) and I start rotating with my mouse it around Z axis (R-Z). It rotates fine until around 20 degrees, when it suddenly capsides the torso and distorts it very bad:



then it continues rotating fine until around 120 degrees, when it capsides again:

Someone knows what could cause this behaviour? I don’t think it’s costraints because it happens before or after I bake them, it makes no difference :frowning:

I wish everyone a very good day

Mmmh, I think it erased my reply.

Anyway let me re-write it :slight_smile:

I did another experiment and I think I found the culprit. OK I was wrong, IT IS constraints causing it, but still I don’t understand why.
I removed all the bones and I kept the offended one (the spine). I noticed how this issue comes out whatever axis I constraint (I’m using Copy Rotation Constraint), but only when I rotate along Y axis.

I did a video to show it, it’s easier for me to explain

Does someone see some logic behind it? I can’t understand it nor how to solve it, I really need to copy rotation constraints in this case.

you should put your .blend file up so some one can examine your settings.

Sure, why not https://drive.google.com/file/d/0B3LZT60RR7SXYmRNRmJnT21jWWM/view

To see the issue, rotate Bip01 Spine1 in pose mode along the Z axis, the issue comes out around 357 degrees, where it will capside the mesh. I’m talking about the middle spine bone in the skeleton made with sticks, not the one made with octaedrons.