Face: concave vs convex

bomastudio

Any method in the API to convert a concave face into a convex one?

If no I suppose to operate as follow:

for each vertex of my face
draw lines to the other vertices fo my face

I get a "web".

Now I need to create a face (for example with the sandbox "from contour").

Then I clean the coplanar face make it my convex face.....

todd burch

That's painful.

Look for a convex hull algorithm.

thomthom

I got a 2d convex hull method in my TT_Lib

Check out this thread: http://forums.sketchucation.com/viewtopic.php?f=180&t=34306&start=15#p302805

bomastudio

thomthom thanks a lot for the suggestion!!!!!

A question: but how many hours you sleep per day? U are an endless source of code!!!!!

thomthom

I occasionally sleep...

bomastudio

it's (of course) works. Thanx U...
Now, with reference to my procedure any ideas how I can replicate with a ruby the "from contour" of the SANDBOX?

Chris Fullmer

The name of that process is delauney triangulation. You can find the math and process of it on the internet, just do a Google Search. That being said, I tried to make it once myself and never quite understood the math notation, so hopefully you have a little bit of math background.

thomthom

@chris fullmer said:

That being said, I tried to make it once myself and never quite understood the math notation, so hopefully you have a little bit of math background.

I never understand the math notations either. But often one can find an implementation in another language or pseudo code. The convex hull code I used in TT_Lib was based on pseudo code in a book I found. I have node idea of how the math fully works, but I managed to translate the pseudo code to ruby.

Didier Bur

Hi,
Delaunay in Ruby is here: http://rhin.crai.archi.fr/rld/plugin_details.php?id=292
Download the required file 'delaunay2.rb', I used this file (credits to P. Bourke and C. Falé) for my points_cloud_triangulation script.
Hope this helps,

jason_maranto

You can also find TIG's update of the Delaunay ruby here -- though I don't think the changes have anything to do with the math:

http://forums.sketchucation.com/viewtopic.php?f=323&t=34232

Best,
Jason.