Issues with weaverbird mesh thickening

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Permalink Reply by Giulio Piacentino on December 3, 2011 at 2:21pm

Hi Andy,

I looked at the files. The bad new is that you'd need to go back to the original mesh and improve it. There are several faces that are extremely thin and long, and therefore should not be subdivided nor applied wbFrame onto.

Also, the position of the mesh itself it too far from the origin, and that makes it even more probably that the subdivision of a face becomes degenerate. This is because computer floating point numbers are a finite set and do not contain infinite precision.

So the first suggestion is:

- redraw manually the parts of the mesh that are not correct. This might take some time but give best result.

     

However, if I did not have much time I'd try to fix it this way:

- download the powerful MeshEdit by Uto.

- move the mesh to the origin and scale it to proper unit sizes.

- then apply Uto's Weld vertices with some tolerance to get rid of the very thin faces. Then unify the mesh normals (also in MeshEdit by Uto) and your subdivision + frames + thicken should then be valid.
I upload this second solution (mesh is embedded), but for the design sake, please also consider the first method.

Cheers, I hope this helps,

- Giulio

Attachments:

• method-2-with-cleanup.gh, 73 KB

Permalink Reply by Andy Cheng on December 4, 2011 at 4:24am

Thank you Giulio! The reason why some of the mesh are long thin is because I used meshtrim and the result was bad as you can see. I did tried delete meshfaces which gave a cleaner result. Is there another of doing that?

I don't quite understand what "the position of the mesh itself it too far from the origin" mean.

Permalink Reply by Giulio Piacentino on December 4, 2011 at 6:36am

Have you tried the attached file?

"the position of the mesh itself it too far from the origin" means that the bounding box of your mesh is something like (-2'570'000 to -2'510'000, -2'900'000 to -2'800'000, 12000 to 14000). You can check that using EvaluatePoint, that tells you the absolute coordinate of a point.

To solve this part, I've moved the mesh to the origin by (1) picking a point on then mesh, (2) moving it to 0,0,0, and then (3) scaling the mesh by 0.01 or another small number using the same point used for moving.

Thanks,

- Giulio