Stands for participating media and it is used to simulate materials like fog, smoke and, in our case, fire. Do the following:
Mode. When 0, the entire object is filled with the volumetric media. When 1, it is filled only partially.
Height. When Mode is 1, it specifies up to what height the volumetric medium fills
the object.
Example: height = 0.5
Scatter.The color of the medium.
Extintion.The density of the medium. 0 is vacuum (no volumetric material).
Example: extintion = 1
R, G1, G2. These parameters account for eventual particles dispersed in the
medium. If G1 = G2 = 0, the particles are too fine to influence light scattering, and R is uninfluential.
Otherwise, it is suggested to use G1 with negative values for back scattering, and G2 with positive values
for forward scattering. G1 has weight R and G2 has weight 1-R. G Values close to 1 approximate an almost
solid volumetric material. Since our fire is homogeneous, all three values will be 0.
| R = 1, G1 = -1, G2 = 1 | R = 0, G1 = -1, G2 = 1 |
| (only back scatter) | (only front scatter) |
Nonuniform. Values between 0 (uniform) and 1 (least uniform).
Example: nonuniform = 1
Min/Max Step Length. Used with the nonuniform setting, the smaller the Min Step and larger the Max Step, the more marked the nonuniformity will be.
| Min = 0.5 | Min = 3.0 | Min = 0.5 |
| Max = 5.0 | Max = 5.0 | Max = 10 |
Light Distance. Used in conjunction with an area light. Tells how far from the area light you will have the highest sampling.
Min Level. Optimizes how photons are stored.
No Global Illumination When Direct. Optimizes calculations when the light that directly illuminates the volume isn't involved in Global Illumination.