I have 3D models of different scale, should I scale the 3D File to fit the camera or should I perform camera zoom in/out to fit the 3D model?
You can use
camera.useFramingBehavior = true;
and later while importing the mesh define the target for the camera:
@labris Love all your help on the forum !!! thanks a lot
If you want to do the opposite, you can call normalizeToUnitCube on the root node of each model to make them all 1 unit size.