# Weaverbird - fixed corner

Hello everyone,

I’m currently trying to learn more about the subdivision process. Although it is very interesting, I’ve a few questions on the “how process”.

1. Basically, I know you have to work with meshes if you wish to work with subdivision with plug-in such as weaverbird. Would you say the best way to archive the final result would be to start from polygones and convert it to meshes? It seemed to me in a few tutorials some people were building their geometry only from meshes only. It surprised me as more commands seems to be available for NURBS than for polygone modelling.

2. I’m trying to figure out how to make an organic form into a rigid frame. Just picture a big rectangle (3D), with a hole in the center of it. I’d like to keep the frame of the rectangle as it is, and subdivise the hole in the center made from a circle. Problem is as I select the 2 surfaces and the hole meshes, the corner of the 2 surfaces got also subdivided resulting into some kind of a fillet with wbcatmullclark command. Tried the others polygone inner command but the result isn’t as organic as it would with catmullclark formula.

Best regards,
David

To better understand Sub-D I would recommend you to watch the Guerrilla CG videos:

To obtain sharp edges in subdivided meshes you have to model them in certain way (add more edge loops near edges or weight them). There are a few nice mesh tools, and there is the Weaverbird plugin to do subdivision on meshes, but Rhino is not ready yet for polygonal modeling (you can not extrude faces, add edge loops etc.) I hope the feature versions will add this capability. But for now you must learn some Sub-D program to create some meaningful low-polygon meshes for subdivision.

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With all that said you can create nice low-poly meshes in T-Splines or Clayoo - just transform the models to meshes, and not NURBS.

Thank you Onetech,

I’m actually using Weaverbird, and I tried to create more edges loops near the edges, maybe I am not using the tool right but I’ll continue to experiment.

Thank you for the share, it definitely worth a look.

I’ve t-splines installed but I’ve not taken the time to learn it yet.

What would be the difference with Clayoo, T-S and weaverbird afterall?

Regards,

Very informative videos. I’ll look forward to know how to sub-d a form but not entirely so I can keep straight part of the form. Didn’t find so much about sub-d/weaverbird though.

Meshes are like bitmaps, and NURBS are a like vector graphics - they are better scalable, and more precise, but finally become bitmaps too.

I mostly use meshes when I need some heavy FlowAlongSrf-type transformations, and NURBS models get just too heavy on my computer to handle. And Sub-D modeling - for animal/human figures which would be a real pain to model in NURBS.