Fx T66011: Transformed objects break sculpt tools
The Pinch, Push, Twist and Clone were not using the object transformation to compute point changes, so the point was way off of the right place.
It would be good if there was a better naming distinction between "point" / "position" and "direction vector" / "delta" types vectors, which require different math. Not saying the code has to be refactored for this now, but something to keep in mind for the future.
The reason for this line of code is unclear, why would the object translation affect a direction vector?
About refactoring, yes I have seen old names that are not clear and need a better naming.
The reason for that is the point is transformed using the delta, so if the original object is rotated, the destination point must be rotated too.
I did not created this operator (it's from old 2.73 +/-) and I tested and it was necessary to make it works when clone rotate objects.