Re: "drawing" grid lines on a surface

Hi Donna,

> I'm trying to figure out the most sensible way to do something. I have a
> surface in 3D space,
> which may be either an Irregular2DSet or a Linear2DSet (onto which the
> Irregular2DSet has been
> sampled). A "data" variable determines height of the surface.
>
> I'd like to "draw" grid lines that follow the surface at particular x or y
> values; this would enable someone
> looking at it to better figure out which parts of the surface relate to
> which x and y values.  Other than
> drawing a bunch of independent "lines" and adding them to the Display
> (which seems a bit
> unwieldy), I haven't come up with any brilliant ideas. Is there a sensible
> way to do this? Is there
> a simple way to create a grid of *lines*, give them a height (or z) value
> by sampling the data set onto them, and
> then display that?

One easy way to do is with ScalarMaps x -> IsoContour
and y -> IsoContour. We usually think of contouring
dependent variables, but VisAD will also contour
independent variables x and y in your Field's MathType
((x, y) - > z). With a 2-D domain Set, the contours will
be contour lines.

I am not sure what the effect will be of contouring
two independent variables x and y simultaneously. If
this causes a problem, you could replicate the Field
with a different MathType ((x2, y2) -> z), and use
ScalarMaps x -> IsoContour and y2 -> IsoContour. But
try the easier approach first.

Good luck,
Bill


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