Re: "drawing" grid lines on a surface

• To: gresh@xxxxxxxxxx
• Subject: Re: "drawing" grid lines on a surface
• From: Tom Rink <rink@xxxxxxxxxxxxx>
• Date: Tue, 11 Feb 2003 14:50:24 -0600

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

If you have problems with the "lines" disappearing into the surface,
try GraphicsModeControl.setPolygonOffset(~1000 or more)