Any idea of how to merge these surfaces?

Hello i’ve tried to merge these surfaces - Merge Surrfaces, Boolean Union but it doesn’t work. What am I doing wrong?

Merging a surface requires a matched surface and ideally a surface with similar properties. You may also walk through Rhino tutorials. Using Nurbs to model landscapes might not the best application for it anyways. Usually terrain is mesh based

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I did all the Dave Schulz tutorial on Lynda. But there aren’t that many indepth tutorials on bigger models. Thanks for the help

MergeSrf only works if the shared edges coincide, are not trimmed edges, and are full length edges. Your edges do not coincide. You can make the edges coincide using MatchSrf.

Hi, I can’t use the matchsrf. It wont let me select any edges

You’ll need to extract surfaces from those polysurfaces first.

I did that but it wont let me matchsrf on the srf that I want.

These are probably trimmed surfaces. Try ShrinkTrimmedSrf and then MatchSrf.

could be a lazy option but you can try with the Drape command to generate a single surface over, instead of merging or matching the existing ones.

Can’t really get the shrinktrimmedsrf and matchsrf to work all the time. will try drape.

ShrinkTrimmedSurfaces shrinks a trimmed edge to the closest isocurve outside of the trimmed surface. Unless the trimmed edge exactly coincides with an isocurve the trimmed edge will remain a trimmed edge. If the trimmed edge being shrunk coincides exactly with an isocurve, for example as a result of a surface being split using an isocurve, then the edge can become an untrimmed edge.

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Surface modelling is not trivial, and much more difficult compared to polygon modelling (which isn‘t easy as well). This is why you should definitly spend more time in learning what each command does and why it is useful. There are tons of tutorials out there, however the best strategy of learning is to test each command until you get it. Even better, find a local mentor who can talk to you. I‘ve seen you are using an educational license so there must be someone around teaching… Matching a surface is a fundamental process/command, which only partially works on untrimmed surfaces. A good modelling process applies Trimming(aka Facing) to end of the local modelling process. Since further working with a „masked“ surface is always problematic for various of reasons, you should almost never match a surface to an trimmed surface edge. Matching a trimmed surface to another is not even possible. And even if you could do that, there is no need in doing this.