xyz quaternion covert to quaternion in splishsplash

[BinglunWang]

Hi,

I'm trying to set rigid bodys quaternion q=(w, x, y, z) form pybullet which is a xyz coordinate to splishsplash xzy coordinate q'.

Do you know how to convert the q to q' in splishsplash? It seems depend on the implementation of splishsplash rigid body system?

Sorry about the different camera position.

Ground truth:
Figure 1,

I tried:
Figure 2, directly swap y and z to make q' = (w, x, z, y) in splishsplash.

Figure 3, as it might flip the chirality, so I make q' = (-w, x, z, y) or q'= (w, -x, -z, -y)