Surface Split Tolerance Problem

Hey,

I am simply trying to split a planar trimmed surface with two curves. One curve is clearly intersecting with the surface while the other is just barely intersecting. The second curve is causing the component to return an invalid surface. Surprisingly, its the larger surface that becomes invalid, not the thin sliver that is split off. Is there a way to increase the tolerance in grasshopper. I tried increasing Rhino's tolerance (in the "units" section of "options"), but it did not change anything. When I split it manually in rhino, there is no problem.

See attached file.

Thanks

Attachments:

srfsplit problem.gh, 12 KB

Replies to This Discussion

Permalink Reply by Lawrence Yun on January 28, 2015 at 10:04pm

So my original model was in inches with an absolute tolerance of .001. I opened a few file in feet (by default) and launched the grasshopper script, and it worked. I then opened a new model with inches and a absolute tolerance of .01 and the script worked. I thought the smaller the number the more precise the geometry...

Permalink Reply by Mateusz Zwierzycki on January 29, 2015 at 1:58am

I thought the smaller the number the more precise the geometry...

...and that's true. If your curve is 0.002 units far from surface, then splitting will not work. If you set the precision to 0.01 then you round the 0.002 to 0.000 and thus it works.

Your problem is directly related with floating point error.

Permalink Reply by Lawrence Yun on January 29, 2015 at 11:36am

But the curve and the surface are co-planar. The surface does get split when the number is .001 (even when I set it to .000001 it works), its just that one of the resultant surfaces becomes invalid...

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