### How to preserve distances between to surface

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Hello,

I wanted to make medieval arch shapes. So, I tried creating a curve using "point wrangle", and then I tried to make another curve on top of it but with an arbitrary distance and using normal vectors to preserve the space, though it collapsed. Unfortunately, scaling doesn't help as it doesn't keep the distance between two arches.

I appreciate any idea for solving this problem.

Attachments:
arch.hipnc (137.7 KB)

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Hello, probably not the most elegant solution but still work here to prevent intersection.
Hope that help.

Other way would be to do more math and done this purely in vex.. but that's another task.

Attachments:
arch_02.hipnc (223.0 KB)
Capture.JPG (190.9 KB)

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Thank you for your reply and the time you spent on this.
I like the idea of removing the points. So, I will implement some code in a PointWrangle to mark the problematic points and then get rid of them.

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Hi,
another option maybe using polyexpand2d on a line.

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arch_mod.hipnc (149.4 KB)

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There's a SOP node worth checking out: isooffset, if you consider some surface offset as a starting point for your solution.
https://www.sidefx.com/docs/houdini/nodes/sop/isooffset.html [www.sidefx.com]
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Although I can set the "Output type" to "Iso Surface" and deal with offset, it creates something that is topologically not so right.
Furthermore, if I increase the offset, the surface tears apart. (Even for a simple sphere)
The problem appears when you want to exturde a shape with some acute angles.
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Plug your arched shape in PEAK->BOOLEAN(union). The peak will work along the normals, and then the boolean solve the self intersection. See image.

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Screenshot 2022-04-12 081820.png (212.9 KB)
Screenshot 2022-04-12 082047.png (56.4 KB)

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That is a great idea. Thank you for sharing this