Happy to do so. But a little history might be a good idea first. When the first computerized desks appeared on the market in the late 70's, basically they were computerized versions of analog systems already in use. Most of the world was using multi-scene
preset desks of some type or another. And then you had a small group of users (mostly between the East and Hudson Rivers, south of 57th Street and North of 41st Street) who were using resistance dimmers (aka. piano boards).
Computerized versions of multi-scene
preset desks yielded the following philosophies:
HTP - since a
dimmer could have multiple "handles" and since multiple masters could be up at once, if a
dimmer was receiving more than one instruction, it followed the Highest
Level.
Preset - each
cue was completely stand-alone. If you looked at the
cue sheets that you wrote to run a multi-scene
preset desk, each
cue contained a value for every
dimmer that you wanted on
stage at that moment.
State: when a
cue was replayed, then, the entire contents of that
cue would be executed (since each
cue was duplicated in its entirety, and since each active light had an actual move instruction - even if it was the same
level as it had been in the previous
cue.)
Computerized versions of piano boards yielded this:
LTP - since a
dimmer only had one "handle", clearly the last
level that you gave it is the one it would use.
Tracking - if you looked at the
cue sheets that you wrote to run a
piano board, only the things that were actually changing were written down. So, only the delta was "recorded".
Move
fade - when a
cue was replayed, only the move instructions were executed.
Tracking and Move
Fade are closely aligned, since they were both ideas derived from piano boards - and they both have to do with moves versus tracked data.... But one has to do with the
cue contents and editing (
tracking), while the other has to do with what is executed.
In the
Eos/
Ion world (just like Obsession), you see "
tracking" and "move
fade" tied together as they would be on a
piano board. Let's say in
cue 1,
channel 1 is at full. It tracks forward until
cue 20, where it moves to 50%. You are in
cue 5. If you manually set that
channel to, say, 75%, it will remain at 75% until you execute
cue 20.... where it recognizes a "move instruction." It will then
fade to 50%. ... this is all "in sequence" ... if you take a
cue out of sequence, the entire contents are (by default) replayed.
The same idea then, is used to manage
cue list ownership. Who is telling a light what to do, and how is that ownership traded off? In
Eos/
Ion, that is also managed through moves. So, going back to our
cue lists above.
Cue List 1/
Cue 1.
Channel 1 at Full. Tracks forward to
Cue 20, where it moves to 50%. You write
Cue List 2/
Cue 1, where you set
channel 1 to 75%. Run
cue 1/1. Light goes to full. Run
cue 2/1, light goes to 75%. If you then hit the go
button to run 1/2, the light will stay at 75% - because the value for that
channel in that
cue is a
track.... and tracks are (by default) not executed on an in-sequence go. You can use assert functions to override that basic behavior.... that forces a tracked value to be replayed. Does that make sense?
Track versus
trace.
Track determines how changes should move FORWARD through the
cue list.
Track this change forward until you encounter a move instruction and stop.
Trace determines how changes should move BACKWARD through the
cue list.
Trace this change back to the "source" of the move instruction. So, if you are in
cue 5, adjust a light, realize it should be at that
level through the whole scene... [Update] [Trace] [Enter]. The
desk will look for the
cue that was giving that light its
current instruction and change the value there. The behavior moving forward through the
cue list is based on
track/
cue only.
In
Eos/
Ion world, [About] is your friend. Leave it open. If you select a
channel, it will give you the "properties" of that
channel.... which includes the source of the
current value (we are adding another way to access that information shortly.).
Hope this helps. Sorry if anyone was bored with the history part!!
a