In exemplary embodiments of this invention, one or more I/O devices accept input from a human user. The input is indicative of a value for each control variable in a set of separate control variables. A computer analyzes the input and outputs control signals to specify a set of separate setpoints. Dimmers adjust the intensity or color of a set of luminaires according to the setpoints. The number of separate control variables is much less than the number of separate setpoints. Having a human control a small number of control variables, in order to control a much larger number of separate luminaire setpoints of luminaires, has at least two advantages: control is faster and control is more intuitive. In illustrative implementations, the luminaire setpoints that are being controlled are not functions of each other.