Complex network surface with rounded corners/shapes


I have som issues with how to use network surface with rounded shapes. what Im working on i cant show as a whole but I can show a similar problem but on another surface.

this surface is constructed with network surface and you can see the green and red lines showing the u and v direction.

where the green and red lines meet in the corner i get some problem with the surface when trying to offset it. In this case i could just make the surface first with sharp corners and the fillet the corners, but thats not possible on my other problem.

this is the curves im workning with trying to make a nice solid out of

how to go about this problem?

i will post the rhino file of the example surface here:
example network surface.3dm (3.4 MB)



Hello, I would go to Solid tools and extrude surface instead of offset.


this is not how you should model such shape! Create the top surface (the big one) just rectangular, curved in normal direction and with as few controlpoints as possible. Then A. offset or extrude it to a solid and apply Fillets to it. or B. Create the outline curves, trim the top surface and offset or extrude then.

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this is what im working on from right view (dont want to show it all here) so its a little more complicated than that? the shell of a chair…

I was doing real car parts for Volkswagen, Bugatti and other manufacturs up to production data, and the data never had been this heavy. You definitly use way to many controlpoints! 7x7 is the absolute maximum of vertices a surface should have. You always need to keep your surface rectangular or fan-alike, with as few curvature as possible. Anything in between gets blended or fillet and trimmed. Your cv distribution is not okay either, and combined with the heavy data involved, you get algorithmic failure and heavy file sizes. Its that simple!

Please have a look at here. You can adapt the principles to Rhino 1to1:

Create a “rectangular” shape with protruding corners and then trim. The physical version would be to mold the shape from a rectangular sheet and then cut to the final shape.

Example of trimmed “rectangular” surface. HalfChairDC01.3dm (167.8 KB)

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good link with a lot of nice tips and tricks. i have done that way before, creating a surface and then trimming it with curves, though in the design stage where i try to find which shape i want to go for i find that it takes too much time. Maybe the best thing is to do my way until the shape is the desired and then make a better surface? or what is your workflow?

i also would like to learn more about curve degree and continuity…

There are multiple ways in approaching a problem. I think if you have issues with form finding, then I wouldn’t do this necessarly with a Nurbs Modelling software at first. Many designer I know are using pen and paper, clay models or a polygon modelling software such as blender. If you are using Rhino WIP you can also try Sub-S Surfaces to do form finding (Autodesk Speedform is an cost intensive alternative).

Only if you have a rough idea on how your shape should look like, I would start creating Nurbs Models. In automotive you even use Bezier geometry only. (A subset of Nurbs, basically a Nurbssurface with cv count = degree +1). But in automotive people actually use Icem Surf or Autodesk Alias as main modelling software. This doesn’t mean you can use Rhino for this. Its just way more difficult to create good quality models. But as I said, many tipps can be applied to Rhino 1to1 and even a model with more controlvertices isn’t automatically a bad model. I think the most important rule is to work precise, simple and to refactor everything constantly. Nurbs Modelling is time consuming and difficult. Take your time.

thanks for the help and by the way, its nice to have a conversation NOT regarding the corona virus situation :slightly_smiling_face: hope yall are fine. I’m working from home infected by the virus… :mask:

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I’m not even following the news anymore. Feels much better now :slight_smile:

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