Surface split: Missing panels after extracting fragments

Good Morning,

I have been using Grasshopper for a couple of weeks, so I am fairly new to this. Perhaps the solution to this problem is obvious, but unluckily I cannot figure it out by myself.

I have created a loft which I am cutting/splitting with a set of curves spiraling up from the bottom to the top. I then extract the (trimmed) fragments and apply a “Deconstruct Brep” to able to use the edges of these fragments. Then I rebuild (untrimmed) surfaces with the edges which I will panelize using Lunchbox later in the process.

Unfortunately some of the untrimmed surface I am trying to create getting missing on the way. I have illustrated my problem below. Why this happens escapes me, I have tried different methods to figure out what is going on, but I am hitting a roadblock here.

Would anyone know what is happening?

Big thank you!

Tower.gh (30.3 KB)


Tower_2021Feb17a.gh (27.9 KB)

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Hard to know if this is more accurate? It uses Clipper PolyOffset instead of Scale.


Tower_2021Feb17b.gh (28.8 KB)

SrfSplit is slower.

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Hello Joseph,

Thank you very much for taking the time! I really appreciate it.

Both solutions work great for me. Do you think the root cause of my problem is because of some inaccuracy caused by the Scale component? It is indeed possible because up to that point all fragments seem to show.

I know have a working solution. I’ll continue to figure out what is going on with my code, because… well, it’s interesting. :grinning:

I don’t know why Edge Surface fails. No good reason that I can see. GH is full of anomalies like that so I don’t waste much time on them. One important different in my code is using Pull and SrfSplit which guarantees that the surface fragments are congruent with the original lofted surface. Scale alone won’t do that.

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Thank you, Joseph. I considered your comment concerning the Pull Curve instruction and I added it into my code. Right before that I convert all the edges to a curve and voila… the anomaly is a thing of the past!

The pink box is the only changes I made compared to my previous version. Odd, but you nailed it!

Thank you for your support, I am really beginning to enjoy this a lot.

Interesting that Pull fixes the Edge Surface problem. However, though indiscernible in this case, I’m not so sure that Edge Surface fragments will always conform to the underlying surface. That’s why I used SrfSplit which is guaranteed to work, even when the fragments have more than four edges.

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