BUG? Extend (type=natural) creates additional point with tiny extension

I noticed that Extend creates additional points on a polyline when I extend a curve by a tiny distance (e.g. 0,006m in a document with units set to meters and the Tolerance set to 0,001 units).

It doesn’t do this with larger extension distances so it’s strange that Rhino adds points for tiny ones.
Bug - extend adds point with tiny distance.3dm (26.3 KB)

This is on Rhino 7.20.22193.9001, 2022-07-12 on Windows 10.0.19044.

I also notice chamfers of curves (with distances on either end set to 0) fail with such short segments. Now this won’t be anything of anyone’s concern, since you shouldn’t normally work on such small things. But for the graph analysis that I am performing it is rather important :slight_smile:

The end of the curve is 5.1 x 10^9 = 5.1 billion units from the world origin. Move the objects close to the world origin and Extend works as expected.

An absolute tolerance of 0.001 relative to 5.1 x 10^-9 is 2 x 10^-13. That is relative magnitudes where the computational accuracy using double precision floating point operations starts to cause problems.

For reference 5129222404 meters is 5.1 million kilometers which is over ten times the distance from the earth to the moon.

Oh wait, now I see. I thought my export would be at the centre of where it was in QGIS, but apparently that’s not the case. Hence the ‘inaccuracy’. Didn’t occur to me to check that, nor will I be able to change the origin, because I would lose the ease of importing and exporting a DXF from QGIS. Thanks for the info.
Apparently, this particular file uses a different centre than what I’ve been using on other DXFs for a subpart of the city.

There may also be a unit or unit conversion issue.