> Using Labview 7.0 and having great difficult graphing the surface of
> an object. I have three variables which are voltages, read with a
> DAQ. The data displayed must be "real time" on the front panel with
> surface change shown as color. I have tried to go through as many
> examples as possible before posting, but with no luck getting the data
> to display correctly. Since this is a raster pattern of the surface
> array structure might not be possible because position x and y do not
> correspond because of different increments in respective direction. (I
> would love to find an example that lets me graph with x and y being
> postion and z just an input variable for color...is this even
> possible? Or is IMAQ a better way to go? (Picture quality > the
> better)
> Background: (Experience level: undergrad) For loop to control y
> direction with two case structure housing each, another for loop to
> control positive x direction and the other -x direction
>
Unfortunately, I'm not on a platform that the 3D graph works on, but I
do have a couple suggestions.
If the XY positions are regular enough to be put into a grid and coerced
to be in the grid, make a 2D array of integers or floats or whatever.
Coerce the XY into the grid and update the value a that location.
Display this 2D array using the intensity graph. Initially the color
ramp uses a black to white through blue ramp, but you can quickly right
click on the fifty on the Z scale and Delete the marker to get a black
to white ramp with white above and black below the top and bottom
markers. You can set the upper and lower markers to whatever makes
sense for your data or set it to autoscale. The updates will take a bit
of time dependent on the size of the 2D array and the size of the graph.
You will be able to lessen the impact by batching a few point updates
if necessary.
Another choice is to use the picture control. For each new point, draw
a circle, rectangle, or other shape with a gray value mapped mapped from
the value. Do this repeatedly without erasing and you may get less
error from the gridding.
Greg McKaskle
