Polygon winding order & vertex arrangement

[Luijee]

Hey all,

Saw this interesting tool on deleting geometry smoothly based on normals, had a go recreating it (hip below).

My understanding of it is to interpolate along triangle edges based on the point normals and create new geometry precisely where

dot(normal, delete_direction) < delete_angle

Geometry positions are correct, but recreating the primitive in the correct order is difficult. On some primitives (ones with only 1 point removed) the winding order becomes CCW and therefore the face normal inverted.

deleteByNormalsSmooth_v05.hip

 

helpful article: http://geomalgorithms.com/a06-_intersect-2.html

If anyone has a clue on how to approach this, or any resources for similar topology problems I would love to know.

Cheers!

[f1480187]

Do you know about PolyCut node feature?

It will work with any attribute, like color.

polycut.hipnc

Note: Try adjusting Cut Value between -1 and 1 on PolyCut. I accidentally left it below threshold in the example file, so, nothing is cut on initial scene open.

Edited December 29, 2017 by f1480187
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[Luijee]

Cool I haven't seen that before, thanks for the example

 

As for where I was going wrong, Matthew mentioned that he recreates the polygon from scratch to have control over the vertex order 

[Neon Junkyard]

On 12/27/2017 at 10:18 PM, f1480187 said:

Do you know about PolyCut node feature?

It will work with any attribute, like color.

polycut.hipnc

That is great, exactly what I have been after for some time now, however is that a 16.5 file?  Doesnt work in 16.0.557, point wrange is pointing to nonexistent parameters

Edited December 29, 2017 by Neon Junkyard

[f1480187]

@Neon Junkyard, 16.5.323. Try adjusting Cut Value between -1 and 1 on PolyCut. I accidentally left it below threshold in the example file, so, nothing is cut on initial scene open. The wrangle interface was improved a bit, but I think it is nothing important that will break the node.