Surfacing problems


#1

Hello guys! I’m trying to learn Rhino surfacing, but still lack basic understanding.
In the first example, I struggled to cap the oval shape. I tried to create it with network curves, revolve, but only patch worked somehow.
In the 2-nd image I also tried network curves, but it didn’t work, as it smoothes on bottom.
in the 3-rd I tried using rail 2 sweeps, but I want additional control over form in the middle, where I added the crossection.
Could you please help me finding correct ways to surface such scenarios?


(Brian James) #2

In the first oval shape screenshot, I can’t tell where patch was used. Can you post a 3dm file? Use the Export command to export only the selected objects too to keep the example clear.

The second networksrf question looks like maybe you’re trying to model the bottom flat surface at the same time. Here’s a similar set up for the top that works with networksrf for you to check out. networksrf.3dm (202.3 KB)

For the keyboard wrist rest, it looks like you may need to model separate surfaces and join them into a polysurface. Again, post a 3dm file if you can and it’ll be easier to tell what the issue is. From the look of it, I’m thinking you need to split the curves to model the surfaces separately.


#3

Hello, and thank you very much for reply!
In the 1-st example I used patch and then trimmed it. It was a pretty awkward way. Now I understand I could make it with revolve, using 2 curves.
In the 2-nd example, indeed it was a mistake including bottom lines. therefore it caused the error.
With the keyboard, I guess you’re right. I will try to use network surface. Should it build surfaces, which connect properly initially, when I surfaced them?
I think those examples were pretty simple, so thank you, as I made changes to network surface command, which now works properly.


(Brian James) #4

Yes, usually an existing surface edge can be used instead of a curve with NetworkSrf and that way you can control continuity too. It’s just a guess without seeing your 3dm file but it looks like maybe a Sweep1 surface could be used for the top and Sweep2 for the bottom edge.


#5

Thank you Brian! I made some retopology with curves. I guess I need to learn some theory behind building curves, as now the resulting surfaces seem a bit irregular. I guess it comes with practice.

retopo.3dm (321.8 KB)


(Brian James) #6

Try the commands Gcon to check continuity between curve ends. The result is reported to the command line and you’ll want G1 or G2 for tangent or curvature continuity respectively. The Match command can be used to match a curve’s continuity as well. Getting the curves flowing smoothly into one another first will help the resulting surface continuity. Also try and surface larger areas to avoid seams… less edges=less problems.

An alternate approach for this form would be to rebuild and control point edit a sphere like this.


I used the Weight command too. ctrl_pt_edit.3dm (677.4 KB)


#7

Thank you very much Brian! I though not sure if I can surface large areas at once. Isn’t there a limitation how much curves curvenetwork can use?
Also, what’s the point of making it one surface like in the last example? As I would like to have it with sharp edges.