Posted by electrosteam on May 14, 2018; 10:37pm
URL: https://forum.librecad.org/Anomalous-Circle-Trim-tp5715994p5715996.html

Well, some quick tests gets some cases reproducing the anomalous behaviour.

I think it gets down to symmetry.
If you try to trim a half-circle and select a point virtually at the mid-point of the retained arc, the machine refuses.
If select close to the trim diameter, works as expected.

But, if then go to the other end of the arc and select again, the erased half-circle re-appears !

So, my plan for new drawings is:
 - do not trim circles with diameters, only chords,
 - when trimming, select the retained arc close to the trimming chord,
 - avoid repetitive trim steps, always ESC, ESC, then do the next requirement,

Still open to alternative suggestions,
John