The help file for converting meshes to SubD indicates that SubD supports sharp creases: [Screenshot (39)] Why don’t the SubD primitives Cone and Truncated Cone seem to use this feature by default? (or do they and what I see is a visual artifact?) Instead, they look like inflated conical balloon…

[image] Nathan Bossett: Why don’t the SubD primitives Cone and Truncated Cone seem to use this feature by default? A common way to start modeling for SubD is to start with a basic shape like a SubD box and then start pulling faces around. Inserting creases for the primitives by default would …

Do you need help on how to crease an edge?

[image] Nathan Bossett: Why don’t the SubD primitives Cone and Truncated Cone seem to use this feature by default? Hi @Nathan_Bossett I think it’s fair that Sub-D geometry is created without any creased edges as default, but maybe it would make sense to have a command line switch for cone, t…

Thanks, but I now know how to do it. Once I knew that edges could be creased, which I discovered only through that related help file, figuring out how was easy via search: the ‘crease’ command. :slight_smile: The problem is that: Rhino, by default, gives you a much less high quality SubD repres…

[image] Nathan Bossett: Why? Because that’s how Sub-D’s - in their truest form - look and behave and what they are programmed to do. Both Crease and the Sharp command, introduced in V8, are a toplayer that, in essence, is altering the original Sub-D surfaces to look and feel more like what we…

Thanks for taking the time on that explanation. The new feature in 8 to gracefully join SubD’s to other surfaces is one I found quite exciting and (I assume?) also compromises on the [image] Jakob Normand: in their truest form - look and behave and what they are programmed to do side. If …

[image] Jakob Normand: Because that’s how Sub-D’s - in their truest form - look and behave and what they are programmed to do. Not just how the code is written. The underlying math has some limitations compared to NURBS surfaces: G2 or G0 (crease) continuity at internal edges. Curvature no…

Hi Jakob - [image] Jakob Normand: there’s a command in V8 called TestSubDEdgeMatch FWIW, It’s no longer there in the version I’m running … [image] SubDMatch: A new command to match SubDs to other Rhino objects SubD This is our current plan. The command would be rem…

Thanks for the background, all. Steve nailed the direct question, which was about whether users really have specific use cases for the current behavior of SubD cone etc. creation. What I was thinking of was trying to produce models which are pure SubD and using small cheats like creased corners to…

SubD Primitives and Creases

Serengeti (Rhino BETA)

wim (Wim Dekeyser) September 18, 2023, 2:19pm 8

Hi Jakob -

FWIW, It’s no longer there in the version I’m running …

-wim

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SubD Primitives and Creases

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