In Blender, we have an option to make Blender camera to be a stereo system. I found this post very helpful in getting the camera parameters (including intrinsic and extrinsic parameters). Yet, the post is mostly for monocular camera. I can assume that in Blender stereo system, the 2 cameras are cloned from each other, hence exactly the same intrinsic parameters. So there left the extrinsic parameters.
Basically, I need to find a transformation 3x4 matrix R*T that transform a 3D point in 1 camera coordinate (usually the right one) to the other (usually the left) in a stereo camera system.