Recently in the community of lighting field, people tend to attach great importance to the qualitative aspect of lighting environment. Going with this trend, it is very essential for lighting planners and designers to be fully conscious of "Direction of Light" as well as "Density of Light" in interior spaces. This paper first brought into focus "Light Distribution Pattern" people sense or feel with their own eyes. In second place, "Cubic Model" of lighting environment was proposed to aim at giving the systematic expression of distribution pattern. In addition to that, a series of numeral simulations were carried out to apply the proposed model to some virtual spaces. In conclusion of the study, the following two possibilities or advantages of "Cubic Model" were cleared: 1) "Density of Light" and "Direction of Light" can be informed in easier indications. 2) It is highly possible to compare reasonably "Light Distribution Pattern" among different lighting conditions and/or different spaces lit.
