I have to load a mesh in Blender (which uses
Y as up and forward axes), modify it and export it (with setting up and forward axes to
-Z) and import it into another software which uses a coordinate system with
Y up and
-Z forward. Later on I export the mesh from this software and import it in Blender for rendering. Since I wanted to get the same rotation in the other software that I get in Blender, I changed the rotation matrix of the other software from Identity to the following:
[1.0, 0.0, 0.0; 0.0, 0.0, -1.0; 0.0, 1.0, 0.0]
Now I get the same exact rotation in that software that I get in Blender when using Euler angles. However, I have to actually use Quaternions and I realized that Quaternions do not have a rotation matrix. I wonder, what is the equivalent version of rotation matrix for Quaternions? Also, how can I change that equivalent-rotation-matrix of Quaternions so that I get the same rotation that I get in Blender?