Hi Dana,

your problem is the same as Evans. The points you supply are written
in XYZ points. The fact that they are on or near the surface is
completely irrelevant. You need to really project the points. See:

http://groups.google.com/group/grasshopper3d/web/XYZ_to_UV.png

For purposes of clarity I've drawn the white (XYZ) point away from the
surface, but it doesn't matter where in space it is.

Let's say the point is located at {1000, 1000, 10}, which is pretty
far away from the origin. The surface is quite small and located
directly beneath it. If you were to drop the point until it touched
the surface it would be at {1000, 1000, 0} (the location of the green
point).

Since the surface was made quite small (it's only 20 units along each
edge), it also has a small domain. Probably something in the order of
{0 -> 20} for both U and V. Thus U0 = 0.0 and U1 equals 20.0 and V0
and V1 have a similar relationship.

Now if you project the point onto the surface, you get the green point
which is now defined in surface coordinates, no longer in world
coordinates like its white ancestor. Furthermore, the UV coordinates
of the green point are about {10,10} (dead in the middle of the
surface).

When you want the isocurves at that green point, you MUST supply the
{10,10} coordinates. Because the {1000, 1000} is so far beyond the u
and v domains of the surface that the isocurves will be way out in
space.

--
David Rutten
[email protected]
Robert McNeel & Associates


On Feb 26, 5:28 pm, dana <[email protected]> wrote:
> Hi -
> Here is a snapshot of what I get from applying the Isocurve component.
> Obviously I am not understanding something simple...
>
> http://grasshopper3d.googlegroups.com/web/isocurve%20problem.jpg?gsc=...
>
> Dana

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