Cue Tracking

Please note that the title was changed from "Tracking" to "Cue Tracking" in order to make this a more focused topic.

[top]Overview


Tracking, when used and understood, makes a world of sense, particularly for moving lights. In 1975, when Tharon Musser and others were consulting with Century-Strand on the development of the Light Palette, they said they wanted a console that thought like a Lighting Designer thought. On a Piano Board, when you put a Dimmer at say 50% in a cue, the handle stays there until a different cue says to change it, regardless of how many cues there are between. So if in Q1 you bring the blue cyc up to 50% and it says that way until intermission, Q99. Cues2-98 do other things, but never affect the cyc. Then the director tells you he/she wants the cyc red during the first act. So in Q1 you record the "blue cyc" at zero and the "red cyc" at 50%. Make sure that Q99 takes the "red cyc" to 0%. No need to change anything about cues 2-98. Almost all console displays use colors to differentiate between a Channel that has tracked from a previous cue and a channel that moves in the current cue. (I don't know Strand's code). Also, for blackouts and other major cues, it's a good idea to insert a "blocking" cue (Colortran used to call this a "clean-up" cue, Express(ion) calls this an "AllFade). This is a cue that inserts a "hard value" for every channel, and thus stops all tracking. A similar outcome, for one time use, can be achieved using "record Q-only."
The best explanation of tracking, especially for moving lights, I have found is in The Automated Lighting Programmer's Handbook, Brad Schiller. Focal Press, 2004. One more thing: don't get tracking confused with HTP and LTP, they are similar, but different concepts.
There was an excellent article on the topic published in PLSN which you can read here.

[top]Example


For the following example I am using Strand's channel color scheme: Purple are channels moving up, cyan are channels that have tracked, and green are channels going down. This means that channels in cyan do not have commands on them.

Also, lets assume that channel 2 controls a special, channel 3 controls a cyc, and 1 and 4 are area lights (It is totally arbitrary). Lets assume that the cues listed comprise one scene, that ends in a blackout (Q6).

Cue Number	Chan1	Chan2	Chan3	Chan4
Q1	50		10	FL
Q2	50	FL	10	FL
Q3	50	0	10	FL
Q4	75		10	65
Q5	0		10	0
Q6			0

So, say the LD wants the cyc brighter for this scene, he can just tell the channel 3 to be at 20 in cue 1 and it would track through the scene. Like this:

Cue Number	Chan1	Chan2	Chan3	Chan4
Q1	50		20	FL
Q2	50	FL	20	FL
Q3	50	0	20	FL
Q4	75		20	65
Q5	0		20	0
Q6			0

Then maybe the LD needs channel 1 to be dimmer in cues 2 and 3. Since this is a tracking console the LD need only change the level in cue 2 as it will track into cue 3. It won't effect cue 4 though because channel 1 has a command in cue 4. Like this:

Cue Number	Chan1	Chan2	Chan3	Chan4
Q1	50		20	FL
Q2	40	FL	20	FL
Q3	40	0	20	FL
Q4	75		20	65
Q5	0		20	0
Q6			0

Now the LD needs the special to come back to full in cue 5:

Cue Number	Chan1	Chan2	Chan3	Chan4
Q1	50		20	FL
Q2	40	FL	20	FL
Q3	40	0	20	FL
Q4	75		20	65
Q5	0	FL	20	0
Q6		FL	0

Uh-oh, looks like that special tracked into our blackout! This is where Block Cues come in handy. The trick is that if you make a cue into a block cue after channels have tracked into it, those channels will still be in it, but no new ones will track in. This is why it is good practice to lay in your black out cues as early as possible and make them block cues. For the next example we are going to assume that Q6 was a block cue before we changed the special (indicated by a "*BL*" for this example).

Cue Number	Chan1	Chan2	Chan3	Chan4
Q1	50		20	FL
Q2	40	FL	20	FL
Q3	40	0	20	FL
Q4	75		20	65
Q5	0	FL	20	0
Q6 *BL*	0	0	0	0

The block on cue 6 forces a hard command on each channel. If the director changed his mind and wanted a silhouette instead of a blackout the LD might keep the cyc lit, so it would look like this:

Cue Number	Chan1	Chan2	Chan3	Chan4
Q1	50		20	FL
Q2	40	FL	20	FL
Q3	40	0	20	FL
Q4	75		20	65
Q5	0	FL	20	0
Q6 *BL*	0	0	20	0

In this case the channel 3's level appears in white because even though it was riding at 20, it was now told to be there again in Q6. In Strand land this would still show up as Cyan, but for the purposes of the example, it shows there is a hard command on the channel.