I have a whole load of surfaces all joinEdge’d together to ensure no leaks.
I now need to offset 2mm inwards but from experience I know the resulting exterior edges if they curve inwards, which they do, will also move inwards so the item in ortho views shrinks a little, so I extend surface beforehand then offset then trim to original overall extents to regain true overall length height etc.
However extendSrf wont work, not without exploding all my careful work. I have joined into the object an object from a forum poster that wouldnt extendSrf, not sure if thats caused the problem, appears not. I dont recall such need to explode surfaces so as to extend them on a previous task.
Any other suggestions ?
It causes a problem, I only want the external edges extending, but imagine an L shaped surface made from two surface abutting, forming the letter L, extending the shorter exterior edge of the cross part of the L upwards also sees that edge get extended beyond the abutt. i.e. abuttment is lost so I no longer have one unified skin to offset. The L is a compound curve so all sorts of unwarranted internal offsets result.