Question about Surface UVs

Where is zero, zero UV [0,0] ?
I would like to define the Surface normal of a plane surface.
Is surface UV works the same way as Curve domains?

Hello - are you asking about how to determine this in the Rhino UI? The Dir command on a surface will show you the positive U (red) positive V(green) and normal. A short blue line will appear if the natural normal (blue line) does not correspond to the brep face ‘flip’ flag, which is not necessarily the same. The Domain command will give you the surface domains. Does that help at all?


Run PointsOn command, then EvaluateUVPt command. The PointsOn command (and F10 function key) displays control points of NURBS surfaces and other objects. The EvaluateUVPt command displays u and v coordinates of any location on a NURBS surface. If you are trying to find 0,0 location, set the Osnap (object snap) to Point and click control points that are close to the surface. After a few clicks you will find the 0,0 location.

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