Merge Triangular Mesh Faces within Angle tolerance ?

Hi Guys,

Is there a way to merge two triangular mesh faces within a pre-defined angle tolerance? I am trying to get rid of any extra triangles in my mesh.

How could I measure the angle between mesh faces? That could be a good start :)

Looking forward to your suggestions,

Many thanks,

Arthur

Replies to This Discussion

Permalink Reply by David Rutten on September 5, 2011 at 3:28am

Hi Arthur,

there is a Quadrangulate component in the latest release, does it not offer the flexibility you need?

David Rutten

david@mcneel.com

Leusden, Holland

Permalink Reply by Arthur Mamou-Mani on September 5, 2011 at 3:33am

Hi David,

Thanks a lot for this component it is very helpful but I am trying to also merge triangles (not necessarily into quads) when they are almost planar. Below is an example of pairs I would like to marry if possible:

Permalink Reply by Dedackelzucht on September 5, 2011 at 3:31am

Hey,

take the vertices,

make Srfs out of them,

take the egdes of the new generated triangelSrfs and rotate them around their SrfNormalVector 90 deg (delte befroe the dupLines)

extrude them in Normal direction

intersect the extrudeSrf with the triangles

join all intersectioncrv

you get polycrv out of two crvs

explode them and measure the angle

Best Regards

DeDackel

puhh...do you get it :-)

Permalink Reply by Danny Boyes on September 5, 2011 at 3:47am

Here's My effort.

Attachments:

MeasureFaces.3dm, 19 KB
MeasureFaces.gh, 12 KB

Permalink Reply by Arthur Mamou-Mani on September 5, 2011 at 4:14am

Thanks so much guys ! That was very fast :)

David, playing with the quadrangulate input helped me reduce even more the triangle count.

My guess was that an Angle threshold of 1 and a Ratio threshhold of 0 is the ultimate merging input. Is that correct?

Danny, I have applied your definition to the mesh and I get a strange pattern with the angle:

When the angle is greater (2), the number is smaller and vice-versa with the small angle (1).

I will use this to merge the triangles and post the results here.

Thanks again guys, it's really nice of you!

Arthur

Permalink Reply by Arthur Mamou-Mani on September 5, 2011 at 4:23am

Sorry Danny it makes complete sense.

The angle is greater when two mesh faces are more open...

Stupid me.

Permalink Reply by Arthur Mamou-Mani on September 5, 2011 at 8:22am

Yipee I managed!! Thanks everyone (a round of virtual beer).

Danny the offset curve is taking 99% of the memory unfortunately and I am planning on using Galapagos on this project which might make the whole thing too slow. The "quadrangulate mesh" component has an "angle tolerance" option therefore I am wondering if there would be a VB method to find the angle between mesh faces? Couldn't find it in the SDK yet...

Permalink Reply by Danny Boyes on September 5, 2011 at 9:29am

Its that age old GH issue of which direction do we offset in. This version offsets both ways and then culls the longer one.

PS Much quicker

Attachments:

MeasureFacesCullOffset.gh, 13 KB

Permalink Reply by Arthur Mamou-Mani on September 5, 2011 at 9:41am

Wow! Danny you are the master of the tree (and the branches), you shift, sort, split, it's beautiful. The definition is so much faster than before. Virtual Champagne to you.

Permalink Reply by Danny Boyes on September 5, 2011 at 9:43am

This ones even quicker, I've managed to get it down to 3ms.

Veuve Clicquot if you please :)

Attachments: