Since, we are integrating over the hemisphere we get the <= 1 condition. This could be because some of the light gets absorbed (or undergoes subsurface scattering? Are they the same?). If we were to integrate over a sphere that might integrate to 1?

keenan

@sickgraph Really not about sphere vs. hemisphere; as you say, if the material absorbs any light at all, the integral will be less than 1. This is true whether we're just reflecting (hemisphere) or reflecting and transmitting (sphere).

Since, we are integrating over the hemisphere we get the <= 1 condition. This could be because some of the light gets absorbed (or undergoes subsurface scattering? Are they the same?). If we were to integrate over a sphere that might integrate to 1?

@sickgraph Really not about sphere vs. hemisphere; as you say, if the material absorbs any light at all, the integral will be less than 1. This is true whether we're just reflecting (hemisphere) or reflecting and transmitting (sphere).