Architecture to learn rotati two 3d objects

I am struggling with the definition of an architecture.

so, this is my problem:

  1. I have 2 3D objects made by points in the space
  2. There is a fixed and a mobile object
  3. I want to predict a rotation matrix and a translation that moves the mobile object to the right position
  4. both objects have a variable number of points

does anybody have a suggestion?