Editing Photon mapping (section)

===Subsurface scattering===

[[Subsurface scattering]] is the effect evident when light enters a material and is scattered before being absorbed or reflected in a different direction.  Subsurface scattering can accurately be modeled using photon mapping.  This was the original way Jensen implemented it; however, the method becomes slow for highly scattering materials, and [[bidirectional surface scattering reflectance distribution function]]s (BSSRDFs) are more efficient in these situations.