SubD Curvature Graph and Surface Curvature Analysis Please

Thank you for your reply Pierre,
Please find attached the file.
What also is the case with the converted Nurbs curvature analysis is that it is very heavy for my potent graphics card. Please find below my system info.

What I really would like is to set up a Zoom meeting and show you how I work as a professional in the marine industry with fine fairing ship hulls and how I use several analysis tools to create high quality fair shapes.
This is a related post about limitations in curvature graph analysis when it comes to Nurbs surfaces: Curvature Graph improvements for Surfaces - #10 by menno

11 Discourse SubD-ShipHull.3dm (3.2 MB)

Rhino 7 SR13 2021-12-14 (Rhino 7, 7.13.21348.13001, Git hash:master @ 7696723f74a63695b3c372a89110c0ca8c78b890)
License type: Not For Resale Lab, build 2021-12-14
License details: Cloud Zoo

Windows 10.0.19043 SR0.0 or greater (Physical RAM: 32Gb)

Computer platform: LAPTOP - Plugged in [100% battery remaining]

Hybrid graphics configuration.
Primary display: Intel(R) HD Graphics 530 (Intel) Memory: 1GB, Driver date: 4-11-2020 (M-D-Y).
> Integrated graphics device with 3 adapter port(s)
- Windows Main Display is laptop’s integrated screen or built-in port
- Secondary monitor attached to adapter port #1
Primary OpenGL: NVIDIA Quadro M4000M (NVidia) Memory: 4GB, Driver date: 10-22-2020 (M-D-Y). OpenGL Ver: 4.6.0 NVIDIA 457.09
> Integrated accelerated graphics device with 4 adapter port(s)
- Video pass-through to primary display device

your subd has some issues (overlapping mesh), not reported by Rhino:

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Thank you for mentioning Gijs!

Sorry I read your message as front/back orientation, not UV orientation. Yes I do see that issue, I’ve added it to my bug list:

For now I guess the easiest workaround is to turn on the curvature graph in both U and V directions. Reducing the density will greatly improve display performance, and since patches made from SubD are quite smooth you will not loose much detail. Exploding the surface and working on small portions is another solution.

Thanks for the links, I’ve read this post and others on curvature analyis /graph improvements for SubD and NURBS and agree we need to improve them. I think we already have a lot of information to work with for now, but I’ll remember your offer to demonstrate to us how you would like to use them and connect with @GregArden (in charge of these tools, I just deal with providing the SubD part) to see if he needs more details.

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Dear Pierre,
Thank you for your reply.
The main issue is that the scale for U and V are always different. So it is not useful to turn them both on.
And yes reducing the density helps a lot.
The reason that I like to have a Zoom session, is to brainstorm about new functionality regarding curvature graph. To show you how I use it today and my ideas to improve the overall functionality.
If @GregArden also likes that, I am happy to share my ideas.

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Hi all,

Overlapping meshes and self intersecting loops is a common modeling problem/mistake. And also very hard to identify.

I was thinking that maybe @pierrec’s misunderstanding in this topic about showing normal direction night be a good way to show these zig-zag loops.

Something that shows this:

Currently this is only kind of visible in ghosted display mode with a backface color option turned on. And only because ghosted + backface is badly implemented so all you see is backface color.



Thank you for your valuable input here

Please set something up. I’d love to see what you have in mind.

Hi Greg, that sounds good. I’send you a PM

Hello ,
I’m revamping this thread because there isn’t any news on the way.
@pierrec there’s something in the Wip8 we can try?

It’s a shame that subd looks like second choice tools



I am curious if this has been resolved. Also, I look forward to your excellent training. From your youtube video on SubD, it seems that SubD is very useful for hull design. It would be nice to know if fairing is possible.

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Hi Chris,

Nope, afaik there’s no progress made in Rhino V8 WIP when it comes to analyzing the surface quality of SubD. Having that said, for 95% of the vessel hulls, Rhino Nurbs is the best way to model and fair vessel hulls. But for example, aft bulb arrangements of merchant vessels and twin skeg arrangements are much easier with SubD.

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