Ripples made when sweeping

The topo lines were imported from autocad. While importing the lines exploded into segments. I joined these segments then proceeded to start sweeping between lines to create a smooth surface.

How do I get rid of the ripples caused when I sweeped? (sweep2) Since I joined these segments should I deleted all of the points before I sweep?

Hi, those ripples could be caused if your model is placed very far away from the world origin or if the model is very large compared to the unit system. If you can post the surface woul help to analyze the problem further.


Hi, how does your surface behave when you have set your scene in Wireframe Mode? Is it just a Mesh Setting which can be easily altered in the Options?

Use Meshpatch to make terrain, it is the best solution. (Just select all the curves and type MeshPatch)
Or ordinary Patch for smaller areas If you really need nurbs.

I presume the ripples are due to uneven distribution of controlpoints on the curves, so I recommend rebuilding them with an even number. This can be a good thing to do before meshpatch too.

Good luck.

My money is on Clement’s diagnosis so far - far from the origin.


The wireframe view looks normal (image 1). When I ghost or render view it appears jagged (image 2).
The object is around ~750,000, 8,500,000, 2000 away from the origin. I later moved the object to w0,0,0 and I can’t find the object even with select all.

Well never mind I have found the object. I re-rendered it and it has correct the problem. Thanks!

Is this Rhino 4? A lot of far from origin issues have been fixed in V5.

Yes it is rhino 4

To optimize the outcome, you might use Meshpatch as @Holo suggested, it could be used directly on the joined segmented lines. If you want to go the _Sweep2 route though, you might get better results once you create smooth curves using _Rebuild on curves made of tiny line segments. Once you create the _Sweep2 surface, it helps to add slashes using the “Add Slash” button marked in the image below so your sweep sections stay more parallel to each other along the rails.