Create terrain by 3d points

Dear all,
I have a CAD file which has a lot of points represent the level of architectural site. I have try to use patch command to create the site surface how ever I found that it is not accurate – a lot of points are not on the site surface.
I wonder if there is a more precise way to do it.

I think the Rhino Terrain plug-in has those tools.
I have not used it myself.
https://www.rhinoterrain.com/en/rhinoterrain.html

Hello - try MeshPatch for this.

-Pascal

Thanks John, I will give it a shot.

Thanks for your reply pascal. But I need the site to be more modifiable. I know you can modify mesh as well. But modifying meshes is not an easy task for me…

Terrain models are generally made with meshes because it’s difficult to pass a smooth NURBS surface through all the data points, especially as landforms are fairly chaotic… If you absolutely need a NURBS surface, then Patch is one of the main ways to get there - the result can be acceptable if the landform is not too radical… The more CV’s and the less stiffness the Patch surface has, the better it will conform to the data points, but with the risk of more “overshoots”.

Another tactic is to make the terrain with MeshPatch, then use Drape with a large number of points to drape a surface over the mesh.

Note also that RhinoTerrain mentioned above will also produce meshes, not NURBS surfaces.

Hi Helvectosaur, I may try drape, it sounds interesting.
I hope there is a plugin or script can dot this task (create NURBS surface) precisely…
Thanks

Helvetosaur via McNeel Forum mcneel@discoursemail.com 于2019年10月21日周一 下午3:55写道:

No there isn’t, for the reasons I explained above. It’s a geometric issue inherent to NURBS, not the lack of a command in Rhino.