# Revision history [back]

### Rotation and Translation question

I've used OpenCV's calibrateCamera function to give me the rvecs and tvecs to try to get the transformation from that of my camera with world coordinates (0,0,0) to that of a chessboard. I'm using it to find the corners of the chessboard with respect to the camera.

I'm confused as to how to apply the rvec and tvec to get the transformation. Do I just do (0,0,0)*rvec + tvec. If this is the case, how do I invert the transformation, as I'll need this for something else as well?

After doing research online I realized I may have to use the Rodrigues() function to get the rotation matrix from rvec, augment that with the tvec, and then add a row of (0,0,0,1) to get a 4x4 transformation matrix. This way, I would be able to get the inverse. However, If that is the case, how do I multiply that by (0,0,0)? Am I just supposed to do (0,0,0,1)*(rotm|tvec, 0,0,0,1)?

I'm not sure which of the two methods to use, I'm doubtful about how to proceed with either of them.