Questions about Point pairs picking Registration(rotation center、)

[Fangxu]

Hello，
I use the cloudComapre for two pointclouds registration by the function of point pairs picking and get a 4*4 matrix. I want use these transformation parameters in SimpleITK (a medical image analysis package) to transform two volume images, but the parameters didn't work, the source volume move further away from the target object.
So I thought the 3D deformation coordinates of the two systems (simpleITK and cloudCompare) are inconsistent. The rotation center，the setting of x,y,z axes and the rotation order of cloudCompare are not clear.
Is there someone know the detail of the transformation of point pairs picking in cloudCompare or know where to find it?

[daniel]

Well, CloudCompare doesn't change the coordinates nor the unit. Therefore the transformation matrix output in the console will make the 'aligned' entity move towards the 'reference' entity.

And mind that the transformation corresponds to a rotation matrix (the 3x3 top left values correspond to the rotation, and the 1x3 top right values, correspond to the translation vector).