In order to understand how humans judge, the softness of light in the daylight environment, two evaluation experiments were conducted. First, we asked the subjects about the judgment of the softness of light, using a picture of the room. Second, we asked them to quantitatively evaluate the items related to the softness of light in the room. As a result of analysis using structural equation modeling has led to the derivation of an evaluation structure that explains the softness of light. It consists of five perceptual observation variables.
