On 3/26/2019 6:06 PM, Jim Wilkins wrote:
"David R. Birch" wrote in message
...
On 3/25/2019 5:12 PM, Jim Wilkins wrote:


Maybe the points were manually "digitized" from a paper print.
https://en.wikipedia.org/wiki/Graphics_tablet
"It can also be used to trace an image from a piece of paper which
is
taped or otherwise secured to the tablet surface."

"These digitizers were... bundled with PCs and PC-based CAD
software
like AutoCAD."

I think the files were generated from some kind of art program,
maybe Corel Draw. The customer was a UWM art dept prof who knew
little about manufacturing. He wanted the finished project for an
industrial show, but he kept modifying what he wanted just before we
thought we were ready to cut metal. His changes meant we went way
over what we had quoted. No one was happy.

The geometry was so bad that I ended using their CAD for reference
only as I redrew what they showed and made something I could use to
produce programs for our LASERs.

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If he assumed from a previous job that it would be manually machined
or the G-code typed in then only the dimension numbers matter, the
drawing could be a freehand sketch. Paper drafting practice was not to
measure dimensions off the print, except in architecture. Circuit
board artworks were taped or plotted on more dimensionally stable
Mylar.
As I originally said, we were sent AutoCAD compatible files, either DXF
or DWG. I discovered the problem when I brought the files into our
AutoCAD and found their dimensions did not match their numbers on their
file.

AFAIK, at no time were dimensions based on a physical measurement of
anything, all we had was a CAD file.

Also puzzling is the fact that the message posted on 3/22/19 is a reply
to a message I left 6 years ago and there is no new text on the post
from .

Another note: all is moot, since I retired 5 years ago.

David