To change this modify the line:
if (minDist < 15) // original number is 15(3.9 meter). I use 9000 (95 meter) meter2 = value
in OpenGL.Designer.cs near the line 526:
To make a full 3d I think one way is to find external software to make the map and after import something like one point per scare meter. OpenGrade is already always searching for the closest point (from the survey line) and if close enough it activate the light bar.
Here I have my modified OpenGrade
It have a valve output for on/off or prop valve (connect in autosteer port),
a laser mode(to level at same height from anywhere)
and an extended distance to level from the line (95m, 300ft)
Edit: removed the link to an old file.