FumeFX supports specific shaders to render the visual data obtained through simulation. You can adjust the parameters of a shader to control the rendered appearance of your fiery effects.
Shader - Choose an available shader from this dropdown list. Currently, FumeFX offers two choices: Standard and FumeFX - Arnold Volume. When either of these shaders is chosen, a set of rollouts specific to the shader are displayed for manipulation
Padding - This option will add voxels around the FumeFX bounding box to allow using displacement shader or similar. For example, one would like to use Arnold renderer and render FumeFX volume with noise displacement, but the grid is simply too small to include all the additional detail. In such situations, user is advised to increase the padding value until rendering result turns correct.
Separate Alpha - By default, FumeFX computes alpha channel in a different way than colors and transparencies used to blend fire and smoke during ray marching. This is useful for the Smoke Shader because changes in falloff values will not alter final alpha channel. It also allows for the Fire Shader to boost up alpha channel without changing final result. This however has a drawback. If you put a transparent object inside a fire, you will immediately notice rendering artifacts. In mental ray, artifacts could be visible if FumeFX grids overlap.