Drag object 1 and also auto drag object 2 that is in different position


I would like your help…

I have a scene with perspective camera and have added some objects…

First: I would like to drag an object not from the center but from anywhere the user clicks ( offset ) this is easy with sub vector e.t.c. but when using that in my case the object gets distorted because I use rotation transformations.

So I was thinking to add a secondary helper object hidden that when you move it, it will also move the main object but the thing is how to know the position of the main object based on the helper object position?

Is there a way to “triangulate” the positions. For example:

Main object start position = x0,y0,z0
Main object end position = x1,y1,z1 ?,?,?

Helper object start position = x2,y2,z2
Helper object end position = x3,y3,z3

Thank you for your help…