1. A method performed by a computing device comprising a processor and memory, the method comprising: accessing a base volume stored in the memory, the base volume modeling translucent material, the base volume comprising voxels that represent geometry and voxels that represent translucence properties of the material being modeled; accessing a mesh model stored in the memory; mapping the base volume to the mesh model to form a two-layered model stored in the memory, the two-layered model comprising a shell and a core; precomputing, by the processor, by sampling light rays entering the base volume, shell radiance texture function (SRTF) values to represent outgoing radiance of the base volume, where, as a result of the mapping of the base volume to the mesh model, the SRTF values are aligned with the shell of the two-layered model, the SRTF values recording scattering effects of the light rays within the base volume; storing the SRTF values in the memory; and precomputing, from the two-layered model, core radiance comprising radiance of the core, and storing the core radiance in the memory; computing, at run time, surface radiance of the two-layered model based on light incident to the two-layered model, the SRTF values, and the precomputed core radiance stored in the memory, and using the surface radiance to render the two-layered model.