vtk file superimposition

How can we save two vtk superimposed files( as a single file)?
For example- right condyle models of the same patient taken at two different time points.

Yes, there are many methods:
1、you can use the merge models module

2、you can import the models to a segmentation and then have a operation

If you want to alin the different models you can use the ‘fiducial registration’ in IGT and analyse the different with the ‘model to model distance’ module