Surface is not smooth even used NetworkSrf, how come?

Hello, I would like to know if someone can give guides about my poor model.
I am building a chair (That’s it). The surface in the image was build with the command “NetworkSrf” Everything seemed smooth until I started to put on materials, many grids started to appear on the surface. I am pretty sure it is not about the material. Could anyone explained me what happened, please?

Hello - please post a file with the input curves and the surfaces.


Post your file.

Images of my poor surface…


First rule: avoid Networksurface if you need high surface quality.


I tried same curves with command sweep2. there are still grids on the surface.

Second rule: start with curves as simple as possible and with consistent structure.
If possible use single span curves. Divide complicated surfaces into smaller patches and match between them.
If you want more help, please post a file.

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If you want to model “clean” and “smooth”, just decompose the shape into low curved and high curved areas. Essential you create very simple surfaces at the low curved areas and let them positionally match.

Then you create blends or fillets in between them. Make sure controlpoints are always equally distributed if you blend and that your base surfaces are similar curved at the area of blending. If you have a good “theory”, your blendings will always look great.

One strategy, less common in Rhino, is to start with 3x3 surfaces, increasing controlpoints on demand to fit a low curved area. Surface should be close to rectangular or fan alike. Prevent singularities etc. Thats essentially the basics of modelling clean freeform shapes…

Thank you very much for the explanation. It is the chair of Eames Daw. I have tried to divide them to half and use sweep2 command but grids were still there when I made the surface and applied the material. I don’t know if my curves are complex or not.The shape of the surface wouldn’t be what I want when there are less control point. How would you suggest to divide them? Here I upload my file, if you are willing to help and give some tips based on my file, I very appreciate!
My file is too big for uploading here, I put in this temporary link:
Thank you!

I don’t see any seat surface at all in that file. Why didn’t you upload the actual surface you are having an issue with? Or post an image in a color other than black and large enough for human eyes to see? Just sayin’…

I created a surface using networksrf, as you’d done originally, and I don’t see any grid pattern. Maybe you are viewing it with flat shading? Try typing in ‘flatshade’ and enter, and see if that helps.

Alternatively, the problem could be related to your materials. Sometimes the mapping is squished in one direction or the other and that can create a series of ripples.