Hi Larry,

If we take an existing shape or fixing then it might be:

A. 'Complex' or highly detailed wall-plug like I am now showing from 'fischer'
or
B. A very 'simple machine screw' like a M6x30.

All these parts have something in common; they have simple outlines
and we have the origination 'somewhere' on the drawing.

THE IDEA/CONCEPT or 'WISH' IS...
I was hoping that 'object' (or maybe its contour-outlines) could be used to create the
clearances or offset-sized hole details. I think it should be this original component that creates
the 'fixing seat' or what you might call the 'clearance fixture' whose shape is 'welded'
into the material.

!! I do not think a user should have to redraw anything in this instance !!

If you see the attachment, and go left to right. This is what I was hoping would be possible
in a 'workflow':

1. LEFT:
Manual operation: User takes 'Plug' (or a machine screw) and this is positioned in the material.
Bolean operation with 'clearance' is appled
OR
Script idea is: USER KEYS in basic shape for the Fixing and/or optional
applies clearance data to xyz 'centre hole position/s' - before making #2 happen.

2. CENTRE: The hole and/or fixing-seat is then made into solid material.
The hole in this instance to hold the plug is in this instance "drilled and countersunk".
IDEALLY this geometry is made from the border-geometry of that fixing.

3. RIGHT: The hole has been made and the screw is pushed in.

I hope this is clear (as mud)?

-- Stefano

link to that file is here:
https://www.dropbox.com/s/a98o0dmcnmda34v/Test-fixing.3dm?dl=0