In OpenGL®, the code is as follows:
glRotatef( -fY, 0, 1, 0 );
glRotatef( fX, 1, 0, 0 );
glRotatef( -fZ, 0, 0, 1 );
This is for rotations/bones.
Rotated first by -Y, then X, then -Z.
As for the 3-D models, reversing only the Z does not work.
Aside from changing the cull order (a minor problem), the objects become backwards. Cloud’s head, for example, points back.
But I am sure if you manipulate the bones correctly, you can make the joints go the right directions to make everything dandy.
If you did that, the obect wouldn’t be mirrored horizontally (though it may be mirrored vertically).
I will personally pursue this matter to see if there is a winning combination for the bone rotations to counter the affects of only inverting the Z.
As for 90-degree fractures, I have never had that.
L. Spiro