I basically followed the outline I posted earlier and left some of the tedious stuff out. This was a proof of principle to see if i could get a 3-d map together in LV that may work fo rmy train layout. Provided the graph is kept small enough, my laptop seems to keep up OK. In a coulpe of years hardware may be able to run this example with larger graphs.
This is how it went.
STEP ONE Get image.
First I found a jpg of part of the layout when it was hanging in my lab. See "HangingLayout1.JPG".
That image was edited to get just the layout as shown in "HangingLayout9.JPG".
I used this image to define the color mapping of the points in a parametric plot.
This image was just to large for my machine to handle so I used Paint to shrink it down into what is shown in "HangingLayout11.JPG".
My machine was able to plot this image on a flat plane that I defined just based on the pixel location and a constant z.
STEP TWO Get colors from picture.
I was disappointed to find that the color map ended up just washing out to a grayscale.
After investigating and thinking about it, I convinced myself this made sense. It tuns out there were about 30K colors in the image and the indicator was not much larger than the picture so I mostly had multiple colors getting mapped to the same pixel.
To get around this I just took a subset of all of the colors. This part of the code could stand alot of improvement. I think there is also a possible bug if the last color gets duplicated due to a poor allighnment of the stars.
STEP THREE define elevation.
The next issue was defining the z-axis. in earlier experiments I had conducted, I decided that the first three dirivitives of an image are not very helpful when trying to define elevation. I did not try that here. I did not want to have to define a z value for each location due to the large pixel count. As an alternative I specify an evenly spaced set of of points that are in turn to spline fit all of the other points. This worked enough to keep me interested because i only had to specify 1 in 10 points.
ENCLOSED EXAMPLE
When you look at the FP before you run it you will see a blank graph and bunch of distordely controls and indicators. Below the 3-d graph is a 2-d array of floats that defines the z-values that worked good for me.
There is also a file path that MUST be set to the proper location to find the file "HangingLayout16.JPG".
Once you run the example the map should be displayed in 3-d as specified by the 2-d array of floats.
As the cursor is moved about the layout, the array that specifies the z values is updated such that you are always selecting the point that dictates the z value at that point PROVIDED, the cursor is at a even multiple of 10. Other times it is close. Another area that could stand some improvement. Ultimately I would like to find a better way of moving about the map but that is what I have for now.
GENERAL COMMENTS
As you are looking at this example remember that a prametric plot does not have to lie in a rectangular matrix like I used for the picture.
If you add about 20 or more contours (by changing the style of the plot) that are based on the z-values, you will see some of the odd edges affect that result from my spline fits. The back side had very little work so I ask that you "pay no attention to the man behind the curtain".
The attached sample is offered as learning fodder for those that are interested. It is also not a good example of LV style! It just a lot of experiments.
I just ask that if you find a better or novel way of using this example, please post your improvement.
There are alot of things I still need to learn about using the 3-d chart and I hope that we could turn this into something more useful than a way to look at my layout without having to visit my neighbor.
Thanks for reading!
Ben
Message Edited by Ben on 04-26-2005 07:36 PM
