Interpolate a closed Curve on Surface

I have a periodic surface (a closed loft) and am attempting to extract an interpolated iso curve through a set of UV points on the surface. I would like this curve to be closed (like the surface) - but when I input a set of (ordered) UV points into the CrvSrf component (with the closed curve boolean = true) the curve does not close in the expected manner - it closes back on itself (see green curve on image). I have tried appending the start point as the last point to force it to re-join, but that did not work.

When I use the 'InterpCrvOnSrf' command in Rhino and click each of these points, re-clicking the first point at the end, I get the closed curve I am after (yellow).

Does anyone have any ideas on how to achieve this curve in Grasshopper?

Cheers

Luke

Attachments:

InterpCrvonSrf1.PNG, 108 KB
InterpCrvonSrf2.PNG, 122 KB

Replies to This Discussion

Permalink Reply by Dedackelzucht on July 5, 2011 at 3:01am

Hey,

I rebuild the defenition, like you explained. And it worked. Can you post your defenition?

Best Regards

DeDackel

Permalink Reply by Lucas Epp on July 5, 2011 at 3:34am

Thanks DeDackel - I think I've found the issue. My set of UV points did not start at 0 and end at 1, which seems to be necessary to form a proper closed curve using this component. I guess the command in Rhino has some logic built in to interpolate between if the set of points does not encompass the entire surface domain in one direction.

It would be useful if the GH component also had similar logic, as often you end up needing to interpolate through a set of points which does not necessarily have points directly on the start and end of the surface domain. Wishlist item, I guess.

Cheers,

Luke

Permalink Reply by Dedackelzucht on July 5, 2011 at 3:36am

yes sorting the points was my first thought as well. But you said you tried and it didi not work. Anyway, hope it works!

Best Regards

Dedackel

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