removing external points on surface

Replies to This Discussion

Permalink Reply by FRiou on July 2, 2015 at 6:02am

Hello,

Here's how I would do it.

Permalink Reply by simbiosi on July 2, 2015 at 6:23am

could you please just send me the same pictures but with the name of the modules ? 

I'm quite new and I don't know the icons :D

thanks

Permalink Reply by FRiou on July 2, 2015 at 6:29am

Sure, here it goes.

I give you the definition as well. Just replace the internalized points and surface with your own!

Attachments:

• External Points.gh, 11 KB

Permalink Reply by Pieter Segeren on July 2, 2015 at 7:14am

Hi FRiou, here's a little hack: to get the edge loop of an untrimmed surface you can just treat it as if it were a curve :) :

Permalink Reply by simbiosi on July 2, 2015 at 7:29am

I did it ...and it work pretty well .... but ... silly question !! 

If I highlight the Cull module I have the external point which i want to remove ... how can I have the inside points ? ..

Attached you can see the picture

Attachments:

• Untitled-1.jpg, 602 KB

Permalink Reply by FRiou on July 2, 2015 at 7:34am

You need to connect the L input of Cull Pattern to the P output of the SDivide (with flatten), not the Crv CP.

Permalink Reply by simbiosi on July 2, 2015 at 7:43am

I solved in another way ... subtracting the point list with the point culled .. and It work :)

Permalink Reply by Joseph Oster on July 2, 2015 at 8:07am

That sounds like what I did using sets.  Our methods are very similar, though it appears to me that FRiou's code might be returning points with "clearance" that are outside the surface as well as inside?

P.S.  MAJOR (faulty?) assumption in my code, using 'Project' Z... perhaps skip that component?  But that was also selecting the points that were actually on the surface...

Attachments:

• surface_points_2015Jul2b.gh, 16 KB

Permalink Reply by Joseph Oster on July 2, 2015 at 6:33am

Here's another way - limited to rectangular surfaces:

Attachments:

• surface_points_2015Jul2.gh, 14 KB

Permalink Reply by Joseph Oster on July 2, 2015 at 7:42am

Here's a better one that works with a variety of shapes:

Note that I set all my random points at Z=-1 and used 'Project' to make sure I get the points on the surface.

Attachments:

• surface_points_2015Jul2b.gh, 18 KB

Permalink Reply by Joseph Oster on July 2, 2015 at 9:52am

This one removes the faulty 'Project' assumption.  It has a two step filter to eliminate random points off the surface:

1. Step 1 selects points very close to being on the surface; using 'Surface Closest Point (SrfCP)', only points where 'D<0.001' are passed along to step two.
2. Step 2 selects points using 'Curve Closest Point (CrvCP)', finding points where D<'edge gap' and subtracting them from the set of points that passed step one, leaving the circled points.

Attachments:

• surface_points_2015Jul2d.gh, 18 KB