Triangulation and Convex Polygons

[MattC]

Thomthom's idea should work great in case there is only one hole in a face, and if You make more vertices on the outside loop. The problem with 'spiky' triangles is that You have only 4 vertices to which the edges are drawn.

Assume that You have two sets of points:
[inner_vertices]
[outer_vertices] - for example 25 points per rectangle side

For every point from [inner_vertices] find closest point from [outer_vertices] and draw an edge between those two.

(Possible problem) when two outer points have the same distance to inner point. Which point to choose ?

Cheers
Matt

[pilou]

Can you post an image with result wished ?

[thomthom]

I was thinking one edge from inner to outer was enough - in order to reduce the number of faces.

But thinking of it more, ultimately everything breaks down to triangles, so if you have a polygonal face in SU - internally it'll be made up of many triangles. The same thing goes for any other software. So converting a face into it's internal triangles doesn't really make the model heavier - in terms of total number of triangles the graphic card needs to draw.

[pilou]

Better to make a retoplogy in 3D party ?

[mrapsouthern]

Hi,

To update my previous post -

Any 1 face with ANY number of holes can be divided into 2 faces with no holes.

where the number of required dividing lines is defined by,

NumDividingLines = NumHoles + 1

please see the following diagram as illustration.

Alex

[gullfo]

slightly off-topic:
http://gamma.cs.unc.edu/propagation/main.pdf
http://sketchucation.com/forums/viewtopic.php?t=36063

[mrapsouthern]

@gullfo said:

slightly off-topic:
http://gamma.cs.unc.edu/propagation/main.pdf
http://sketchucation.com/forums/viewtopic.php?t=36063

It is off topic - but I am very familiar with that work - it's quite a coincidence you posted it....

[gullfo]

@mrapsouthern said:

does the SU-Catt converter then create the correct output?

[gullfo]

@mrapsouthern said:

It is off topic - but I am very familiar with that work - it's quite a coincidence you posted it....

i'm trying to re-work Jonathan's SU-ABEC to use ABEC 2.0 but it's tough because their model shifted a lot... http://www.jonsh.net/blog/?page_id=197

[mrapsouthern]

Glenn,

Small world. I know Jonathan well also. Have we met?

Anyway, Yes, if the faces with holes are partitioned as shown the output of SU2CATT is interpreted correctly.

Cheers
A.

[mac1]

Will merging vertices help?
Your model reduced from 200+ to ~72

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[mrapsouthern]

Merging vertices looks like it helps for that case. I can't check it for multiple holes though right now. Thanks