[help] Create surface with 3 cuvers rail

Hello Guys.
I am a newbie in Rhino. I have a problem with creating surface form 3 curves rail. Please see the attached file and help me. 3 curves rail in green color. Red curve wants to create a surface.
Thank you so much

SF.3dm (22.7 KB)

Hello - it looks like Loft is what you want here, maybe? Not sure what the red curve’s part in all of this is…

If you want to incorporate the red curve, there is not a tool in Rhino for that - I am not at all sure what the expected outcome is.


Thanks, Pascal.
but,My mean, I want to create a surface with the Red curve and offset with 3 green curves.

Honestly I don’t really understand what you are after, probably worth further clarifying it a bit?

Sorry, Zach, my English is so bad, Please see this pic, I want to create an inside surface and it offset with outside surface, My problem, I have all input data for out surface, but inside surface, I have only a curve and know it is offset with outside surface.
Thank you so much.

Xy, you might try Offset surface with solid option off. —-Mark

sorry, I tried but it can not offset surface to curve, if you can, please download my file and try.

When you do offset, you need a distance for it as offset is to maintain cosistant distance between the old and new object.

See attached, you can’t offset it to get a surface that conforms your inner curve, because the distance is not even consistent. Unless you are thinking of uneven offset which is probably beyond my knowledge.

One way I can think of doing it is to extract the control curves, and find the normal of each one, establish some sort of plane between the outer curve and inner curve, then do a NU scale to each outer curve, then re loft the scaled curve. But I doubt that is what you want though.

Let’s hope someone else comes with a solution.

SF.3dm (141.3 KB)
SF.gh (15.7 KB)

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Great Thanks Zach.
It is my want.But I open your file and have a error with newer version Grass, and in my computer, inside surface clash with curve, not same your pic @@!!!

Please update your Rhino to SR 9.

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Okay, Thanks Sir