@David
I have been using this controller with great success: http://dmxking.com/led-pixel-c...
I'm not sure how many universes Juriaan is looking to control. The device supports 4 channels, each with upto 4 Universes (I have tested with 2 each). So in theory this device can control ~2700 rgb leds.
And Isadora can connect to multiple devices simultaneously. (myself I have only tested this with: http://dmxking.com/artnetsacn/... alongside the other 4 channel unit)
If you are using strips, it is likely that powering the leds will become your biggest issue. The voltage will drop at the strips get longer, and this will cause first the leds to produce in correct color (white will become orange, then red) and finally they simply will not function.
This is handled by injecting power along the way. (there are a few way to handle this, so some research is needed)
Isadora's actors for Artnet output/pixel mapping, can only capture pixel values from the Horizontal or Vertical lines of a video. I have had no problem rotating video so that I could take a angular element, and grab it from either the Horizontal or Vertical, but it does take some planning.
Mark has written a tutorial that walks thru the process of setting up LEDs + ArtNet in Isadora here: https://support.troikatronix.c...