Rotate UCS and apply this routine to get BBox, then extract only width (red line)...
Thank you Ribarm!
Works !
But I was hoping for a mathematical solution. . .
Because this routine does a number of very spectacular things,
while I'm looking for something that can't be seen,
that makes calculations "in secret" ...
But I realize that it is a very complicated thing!
I have to try to do something only for lines, circles and arcs...
It shouldn't be hard...