OffsetSrf works in one file but not another

[miano]

I am curious how this can occur. I had file created in Rhino 6 that I opened for the first time in Rhino 7. I used curves in the file to create a poly surface.

Then I did OffsetSrf (sharp) 3/4" inward (concave). This failed. It used to work that last time I opened the file.

Created a new file with the same tolerance (1/256) and copied the poly surface to that file. Then I did the same offsetsrf and it worked.

I was wondering how the same operation on the same surface would produce different results in different files with the same tolerance.

Problem OffsetSrf.3dm.zip (80.4 KB)

[encephalon]

i can not see anything wrong, you might want to post the original file and the file where the curves produced bad surfaces for offsetting.

also offsetting does not produce a clean result in general you have a tiny overhang here