Hi Petr, thanks for reporting these!

Re: sphere/line merge - I'm sure you guessed what is happening here, there is some detection if the line is on one of the world planes and if it is it uses that plane's normal as the projection direction. But in that case you are on 2 world planes, and when that happened it would just pick the first one of x, y, or z axes.

I've made a slight adjustment to this so that the z axis will be preferred in this case instead.


Re: curve fillet - thanks for narrowing down the cause of this failure! It will be difficult to allow segments to be completely consumed in general when there were fillet vertices at the ends of the segment (like a small line out of a polyline being consumed by a large radius), but I should be able to tweak things to handle this case to allow a G1 segment to be consumed, where it was not crossing a fillet vertex. I'll dig into that tomorrow.

Do you think that I should put something into Join to automatically glue arcs of the same circle into larger single arcs?

- Michael