Luminous intensity is the light energy per unit time emitted by a point source in a particular direction.
Luminous intensity is used to describe the directional distribution of a light source; that is, it measures how the intensity of the light source varies as a function of the outgoing direction.
The candela (cd) is the unit of luminous intensity. A candela is a lumen/steradian (lm/sr). The candela was originally defined as the luminous intensity emitted by a single wax candle.
In 3ds Max, luminous intensity is one way to specify the intensity of a photometric light. See Intensity/Color/Attenuation Rollout (Photometric Lights).