# Geometry nodes: how to make a surface from (bridge between) generated curves?

My goal is to generate an interesting surface that is easily fabricated with a 3D printer - e.g. minimal overhangs.

I can generate nice sets of closed curves, which I can duplicate, scale, and offset in Z.

But I’m having no luck figuring out how to turn this into a surface.

A simplified example:

The object on the right is what I’d like to generate. I created that by applying the geometry nodes modifier and then manually bridging between the loops. As there’s going to be 10’s - 100’s of these, I’d like to do this with geo nodes .

I have tried using the curve-fill node, but that set’s Z=0 for all points.

I’ve watched some tutorials that capture attributes from curves and then apply that to generated mesh data. My attempts at this haven’t worked- and I’m a little confused about how to make sure the data is mapped correctly from the curve points → matching vertices in the generated (curve → mesh) mesh.

Note - I do want to be able to rotate and offset (+ve Z) the upper most curves so the tops of the “craters” also create a novel terrain between them.

This operation is called lofting, Try searching the forum for geometry node lofting

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Thanks @SterlingRoth. I only found lofting mentioned in higgsas’s post about his amazing pack of geometry nodes (very tempting to buy) and this post re making a wing. Which links to an Erindale video tutorial. Looks like it’s doable, but not trivial.

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Maybe to get an idea you maye have a look at this:

…the position of the lofted spline is controlled in the BOX INDEX group and not routed outward yet… and of course you want to have to make a surface…

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Higgsas is kind enough to keep free versions of the examples available to BA users like here.

… although I do recommend you buy their pack.

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Thanks @Okidoki !

Wow, thanks for pointing that out @zeroskilz. I’m very likely to buy higgsas’s pack eventually- but I’d like to learn how some of these things work in principle first before I have to many things installed that just do magic

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understandable… i went your path but backwards… i bought higgsas’ pack, but have yet to use them while i learn GN on my own (well, with google’s help, ofc. )