I believe
Wybron makes/made a
system.
Martin makes/made one also.
One (don't remember which) required multiple receivers to triangulate the performer, who wore a transmitter. Data was sent back to the
console, which would
track via however many moving lights. All you did was make a
cue to follow X transmitter in whatever color/
gobo. The other
system used a device which looked like a tv camera. It shot a
laser beam and you "painted" the performer, which again sent data back to the
console and the lights would follow depending on the
cue. It was similar technology to how the military paints a target for its guided missiles.
Or it could be followspots.
As for writing cues for each performance, I don't see that as a big deal. I haven't seen SYTYCD, but they do new cues for each performance on Dancing with the Stars and American Idol. The focus points are fairly similar, so it's more a matter of combining a
ballyhoo or two, a
gobo palette and a color
palette for each number. My guess is the designer for those shows gets costume design and colors and music about two days before dress rehearsal, so they write most of it then using a pre-vis program like ESP
Vision, tweak it out during dress, and run it on the show.
You can really break DWTS down to four or five lists: the band and the upstage area; the color cubes around the
dance floor, the moving lights around the
dance floor, the overhead stuff, and the performer followspots.