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stephenl

Cut polygon faces from polygon lines

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Hey guys been awhile since I used Houdini, how can I cut polgygons with polgyon lines? I have a series of straight lines that I want to divide a box from (preferably only one face of the box that faces directly at them)

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Hey guys been awhile since I used Houdini, how can I cut polgygons with polgyon lines? I have a series of straight lines that I want to divide a box from (preferably only one face of the box that faces directly at them)

May be ray using min distance and a curvesect is what you want to try.

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If you have a bunch of straight lines, then why not use the Clip SOP?

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Is it what you're looking for?

Edited by vi_rus
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interesting .. where is otl 's link ?

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I didn't share this tool. But I used PolySplit node so you can repeat this pretty easy.

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Did anybody succeed in re-building this? I guess somehow the curve positions get transferred into the split locations which seem to be in another context. Seems that it is made up by the primitive number, edge number and a divider. No idea how to convert the curve coordinates into this. Anybody an idea?

Afterwards I would disconnect the edges across the split to separate the polygons.

Could anybody help me out?

P.S.: Could this also work with polygons with more than four edges?

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Had a play, got something that sorta works. Reading the help page for polysplit, noticed it accepts a few different ways to define the cuts, including prim+uv, which is easy to get with vex and xyzdist.

 

post-7292-0-51459000-1447648865.gif

  1. One wrangle takes each point on the curve, uses xyzdist to get closest prim and uv of the target mesh.
  2. Second wrangle collects all the hitpoints and stores them in a single detail string, in a format polysplit expects.
  3. Polysplit uses details() expression to read that string into itself
  4. Groups pre/post split to isolate the new points, do things if required.

Bit glitchy, that vimeo one is obviously doing some clever things under the hood, but I'm guessing the core of how to drive the polysplit procedurally is something like this.

 

polysplit_procedural.hip

Edited by mestela
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