Wrong List sequence - Surface Split

Hey all,

I am trying to write a Grasshopper script for Stairs made out of two curves. I loft the 2 curves then divide the curves and use the points to get lines which split the surface. After that i want to move the single surfaces with a series along the Z vector. But somehow the order of the Surfaces got messed up after the Surface Split so the series doesn’t work well. I tried a lot of shifting and culling but couldn’t get a good result - Would be realy nice if you guys could help me fixing the order :wink:

Treppen.gh (15.7 KB)

I guess you’d better to shatter input curves rather than splitting the surface.
It seems that you forgot to internalise your input curves.

Treppen_re.gh (19.7 KB)

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Surface Split is not the type of operation that guarantees or keeps order as it is not a type of command that is iterative, it happens all at once.

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I have done it like that befor and it works well for a lot of different stairs but when you got a inner circle sourrended by a square both are divided in equal length with the konsequent that the stairs aren’t perpendicular to the circle - thats why i want to use lines to divide.


For the lines which divide to loft i used offset and and closest point to get those perpendicular lines on the loft.

Thanks, thats a good fact! I was realy confused why it came out mixed up.

So I approached it a little differently. Because the lines are in order, I picked line index 0 and index 1, then index 1 and index 2 etc. I then used those pairs to loft a surface which you can then move in the Z directions as needed. Not the cleanest solution, however it appears to work. Hope this helps.
Billmy version Treppen.gh (18.8 KB)

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Try to check this plugin if those components wouldnot allow you different strategy https://www.food4rhino.com/app/sasquatch-utilities

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I like your solution, super clean and easy. Thanks for sharing.


Try this with shift by 2 and reverse curves list input


That works well for this particular situation but it would be nice to have a more general solution. I could probably creat such a solution with more operation for curves…
Do you guys know a plugin with more curve operation beside pufferfish?

You can sort surfaces centers along curve

I think this work with various situations

Treppen.gh (14.1 KB)

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Thanks a lot Seghier! that is exactly what i was looking for :slight_smile: