Didn't notice how interesting it is until I read the paper: https://cs.dartmouth.edu/wjarosz/publications/jarosz08radiance.html. Basically in our 3-1, we are only intersecting the ray with the surface of the object. However, if we take particles inside media into consideration, then we observe multiple different effects. For out-scattering specifically, we should use an analytical phase function to model the the light scattering, and depending on the effect we want, we can apply bask-scattering (which leads to a higher percentage of light reflecting back to the emission direction); isotropic-scattering (a perfect circle with same scattering across all direction); or forward-scattering (where most rays travel along its original "intentional" path).
Didn't notice how interesting it is until I read the paper: https://cs.dartmouth.edu/wjarosz/publications/jarosz08radiance.html. Basically in our 3-1, we are only intersecting the ray with the surface of the object. However, if we take particles inside media into consideration, then we observe multiple different effects. For out-scattering specifically, we should use an analytical phase function to model the the light scattering, and depending on the effect we want, we can apply bask-scattering (which leads to a higher percentage of light reflecting back to the emission direction); isotropic-scattering (a perfect circle with same scattering across all direction); or forward-scattering (where most rays travel along its original "intentional" path).