You may have found a case or two where this works, but the fact of the matter is that you can't accurately map a 3D space with only 2 pieces of information. It could be done with XYZ coordinates or Pan, Tilt, and distance, but not with only pan and tilt.
Here's a good example of why: When the hang position of a fixture changes, the relation of positions does not remain constant.
Imagine that you have a FOH truss with a single moving head hung dead center.
Imagine also that you have 2 positions on the quarter lines, DSL and DSR.
Let's say for example that the DSR position is pan -20° and tilt +45° and that the DSL position is pan +20° and tilt +45°. Notice the difference between the pan values is 40 degrees.
If the position of the FOH truss moves back farther into the house, the positions might be at pan -10° / tilt +60° and pan +10° / tilt +60°. Notice that now the difference between the pan values is only 20 degrees.
This is a fairly simple example with only 1 fixture and 2 positions. Things get even more complicated when you have fixtures scattered about the stage.
What this boils down to is that you can't accurately define a point (your focus position) in three dimensional space with only two pieces of information.
I hope this clears things up. XYZ positioning is still an open feature request and would offer the functionality that you desire.
You may have found a case or two where this works, but the fact of the matter is that you can't accurately map a 3D space with only 2 pieces of information. It could be done with XYZ coordinates or Pan, Tilt, and distance, but not with only pan and tilt.
Here's a good example of why: When the hang position of a fixture changes, the relation of positions does not remain constant.
Imagine that you have a FOH truss with a single moving head hung dead center.
Imagine also that you have 2 positions on the quarter lines, DSL and DSR.
Let's say for example that the DSR position is pan -20° and tilt +45° and that the DSL position is pan +20° and tilt +45°. Notice the difference between the pan values is 40 degrees.
If the position of the FOH truss moves back farther into the house, the positions might be at pan -10° / tilt +60° and pan +10° / tilt +60°. Notice that now the difference between the pan values is only 20 degrees.
This is a fairly simple example with only 1 fixture and 2 positions. Things get even more complicated when you have fixtures scattered about the stage.
What this boils down to is that you can't accurately define a point (your focus position) in three dimensional space with only two pieces of information.
I hope this clears things up. XYZ positioning is still an open feature request and would offer the functionality that you desire.
