Following this post: [image] Is Rhino Breaking My Geometry? Offset Lines Fail Parallel Rhino Rhino is driving me crazy. I created all the lines in the attached drawing using Offset (they’re all degree-1 curves). When I export to AutoCAD, most of them are detect…

Note the issue is real - albeit very small, and it does need to be corrected. Many people don’t understand how Join works and how it has since forever. When Join encounters two curves that do not intersect, but are closer than 2x the file absolute tolerance, it averages the endpoints and moves bot…

[image] Piotr: I’d use fillet with 0 distance Connect is supposed to do exactly that. It was actually added to Rhino in like Rhino V2 (V3?) because people complained that they had to continually reset their fillet radius (which is sticky) because they were using it with 0 to connect and with…

@Piotr Connect, Chamfer, and Fillet with radius 0 do not affect the geometry when the intersection distance is tiny (by not affect i mean they don’t extend and trim the lines to intersection as expected). @Helvetosaur said this distance is 2× the tolerance, and he is probably right. Trim and Extend,…

[image] Helvetosaur: My attitude is that this bug has probably existed for a long, long time and since there has not been much (if any) noise about it until now, I expect that the possible inaccuracy has not resulted in major disasters. I’ve checked this behavior in Rhino 5, and it’s definite…

[before_connect] Please take a look at what this behavior forces me to check manually before I can even connect the lines in the attached file. It becomes a serious issue when I need to verify the geometric ‘equivalent of 1+1=2’ each time. And what does it mean when the software reports ‘2.000001…

[image] Helvetosaur: Many people don’t understand how Join works and how it has since forever. When Join encounters two curves that do not intersect, but are closer than 2x the file absolute tolerance, it averages the endpoints and moves both curve endpoints to that average point. That is how it…

Give this post to the AI and tell it to explain what the issue is. I’m sure it will be easy for it to explain it to you in a way you can understand.

[image] Ar00302: . It becomes a serious issue when I need to verify the geometric ‘equivalent of 1+1=2’ each time. And what does it mean when the software reports ‘2.000001’ instead of ‘2’? The value 2 is an exact integer, but 2.000001 is a floating number. You might want to read up on how …

[image] Helvetosaur: Many people don’t understand how Join works and how it has since forever. Regardless of how join works users have the option to use the Connect tool which is supposed to extend the curves and trim them at the intersection point. There is really no excuse for that failing…

[image] Helvetosaur: The absolute tolerance value you set on a file is often misunderstood by Rhino users. Grossly oversimplified it means you don’t care about inaccuracies smaller than that Tolerance means the user will tolerate some inaccuracy when there is a trade off between between accur…

Critical Rhino Bug: Chamfer/Connect + Join Corrupt Line Orientation

Rhino

brian (Brian Gillespie) December 9, 2025, 11:51pm 33

RH-90695 is fixed in Rhino WIP

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Critical Rhino Bug: Chamfer/Connect + Join Corrupt Line Orientation

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