This plugin provides a volumetric path tracer that can be used to compute approximate solutions of the radiative transfer equation. Its implementation makes use of multiple importance sampling to combine BSDF and phase function sampling with direct illumination sampling strategies. On surfaces, it behaves exactly like the standard path tracer.
This integrator has special support for index-matched transmission events (i.e. surface scattering events that do not change the direction of light). As a consequence, participating media enclosed by a stencil shape (see Section 8.1 for details) are rendered considerablymore efficiently when this shape has no 17 BSDF assigned to it (as compared to, say, a dielectric or roughdielectric BSDF).
• This integrator will generally perform poorly when rendering participating media that have a different index of refraction compared to the surrounding medium.
• This integrator has poor convergence properties when rendering caustics and similar effects. In this case, bdpt or one of the photon mappers may be preferable.
17 this is what signals to Mitsuba that the boundary is index-matched and does not interact with light in any way. Alternatively, the mask and thindielectric BSDF can be used to specify index-matched boundaries that involve some amount of interaction.
- Max. path depth : integer
- Specifies the longest path depth in the generated output image (where -1 corresponds to ∞). A value of 1 will only render directly visible light sources. 2 will lead to singlebounce (direct-only) illumination, and so on. (Default: -1 -> 24 @ blender)
- Russian roulette starting depth : integer
- Specifies the minimum path depth, after which the implementation will start to use the “russian roulette” path termination criterion. (Default: 5 -> 10 @ blender)
- Strict Normals : boolean
- Be strict about potential inconsistencies involving shading normals? See page 154 for details. (Default: no, i.e. false)
- Hide Emitters : boolean
- Hide directly visible emitters? See page 149 for details. (Default: no, i.e. false)