Why have fixture modes?

Modern lighting fixtures are complex, particularly ones that move and have multiple colour mixing capabilities. Add 16-bit control to many attributes and you end up with a fixture that requires over 100 channels of control to just get it working. Not everyone wants to have to deal with that many channels. Not only does it require anything but the smallest of rigs to require more than 1 DMX universe, but there are many occasions when the user doesn’t want to have to wrangle 6 zones of 16-bit multi-colour mix fixture just to get a red splodge of light on the drummer.

Fixture makers give the user different mode options so that they can cater for a large range of use cases, including as many features as possible while allowing the user to pick and choose which are the most important to them. This results in a simplest, smallest channel count mode, a complex, huge channel mode, and some inbetween. A lot of the time in professional lighting practice, the middle-sized modes are chosen for their balance between features and ease of control, plus being a little more frugal on the DMX channel count.