How do I turn a 3d dxf survey file's inconsistent contour to a contoured model?

I imported the dxf file to rhino, and how should I quickly build up a model based on those inconsistent contour lines?

TERRAIN.jpg

Tags: grasshopper, terrain

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Permalink Reply by Dedackelzucht on June 29, 2011 at 1:09am

Hey,

do you want to get a Srf model? If yes, sort the lines by the z-value and loft them (does not work this easy if you have more then one hill).

otherwise defineinconsistent in this contaxt. I maybemissunderstand you.

Best Regards

DeDackel

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Permalink Reply by David Rutten on June 29, 2011 at 4:02am

Lofting won't work, as these contour lines do not have consistent topology. Some contours may be closed, while others are open. Some contours will consist of a single curve whereas others consist of a group of curves at the same elevation. Lofting can only be applied to a setof curves that have the same topology.

To do from this to a Nurbs surface pretty much your only option is to 'fit' a surface to the contour data. There's two ways that spring to mind:

Patch. There is no Patch component in Grasshopper but the command can be invoked from within a VB/C# component and Rhino5 has a Patch SDK function.
Create a delaunay mesh from the contour lines (divide them into points first), then move the control-points of a planar nurbs surface upwards until they coincide with this mesh. This approach can be achieved fully inside Grasshopper.

David Rutten

david@mcneel.com

Poprad, Slovakia