Pan and Tilt Example

The Home position for pan and tilt on most DMX lights is 50:50 (or 32767:32767). This positions the light such that you will have maximum movement in each direction before encountering a pan-stop or tilt-stop. For a light that has a total pan range of 360 degrees, with the control channel set to half, you are sitting at 180 degrees. Taking the control channel to full will move the light 180 off axis towards a stop. So, to summarize, a value of 50% means "go to Home", and a value of 100% means "go to the pan-stop 180 degrees from Home". Figuring out that 90 degrees is half way in between those two values is easy. That would be 75%. And a 45 degree pan from Home is, again, half way between those two values or about 63%. Now it begins to get a little too complex for the programmer to calculate quickly.


To add to the complication, imagine you have another light in the rig that has a total pan range of 540 degrees.



Now the numbers you just figured out for the first light mean nothing to this one. Worse yet, if you grab them both and pan them in tandem, you would get completely differing results:


The angles of pan are completely different. The beams of light are not even close to parallel. You can see how this can be very frustrating if you have a mixed rig. With Natural Language Control, the Pan attribute is represented in real-world units of degrees. Therefore, when you talk to the light, you tell it to pan so many degrees:


Forty-five degrees is forty-five degrees. This makes controlling a rig that is made up of different types of lights easy to communicate with and easy to understand.


Since Natural Language Control doesn't figure out DMX values until the very last second, it can also alter the way in which the conversion is done at run-time, producing new and exciting methods of transition during the fade from cue to cue. Various attributes, such as position and color lend themselves very nicely to working in different ways. Color Space is described in detail below, but let's examine how we can move from one place to another on stage given two stored end places.




Moving lights achieve movement by physically moving the source with two motors housed within a yoke. This Pan/Tilt relationship equates to a polar coordinate system using azimuth and elevation. When you pan more than you tilt the light will move in an arc:




We have become used to this characteristic movement of intelligent lights. Very good moving lights that move extremely smoothly are sometimes described as moving in an organic manner or looking like they are operated by a follow-spot operator. People are quick to forgive the fact that they are always moving in this arc pattern. Natural Language Control gives you the option of how the light will move. It doesn't have to move in an arc. When a follow-spot operator moves a light from point A to point B, the light normally travels in a straight line.




Choreo has a Positon attribute called P/T Mode that alters the way fades are calculated when you advance from one position to another. If you record a memory or a cue using specific Pan and Tilt values and specify the P/T Mode to be Linear Movement, the end points of the move do not change, but the intermediate steps of Pan and Tilt needed to get from the first position to the second position do change. It becomes a transition that forces the Pan/Tilt mechanism to travel the beam of light in a straight line:



Next: Zoom Example