This page provides information on the PhoenixFD Atmosphere settings.


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The Atmosphere settings are applied to all Phoenix simulators in the scene that are set in Volumetric Render Mode. They also apply to all Particle Shaderobjects that have their Render as Geometry setting turned off, because they are rendered as standard 3ds Max atmospheres.




Atmosphere settings




Gamma Correction | gamma_mult – A multiplier for the gamma of all Phoenix objects in the scene.

Export and render in V-Ray RT as VRayVolumeGrid | atmosexportasvolgrid – (V-Ray only) This option forces the Phoenix simulators to convert to VRayVolumeGrid objects when rendering in V-Ray RT or when they are exported to a .vrscene file, which enables them to render on machines that do not have a Phoenix license. Note that an exported VolumeGrid will correspond to the features available in the respective V-Ray version that will be used to render it.

Use Probabilistic Shading | prob_rend – This mode works only for Simulators in Volumetric render Mode and Particle Shaders which have their Render as Geometry option disabled. When Use Probabilistic Shading is enabled, the volumetrics will select a only few samples (based on the smoke density) along each camera ray, and evaluate the volume lighting at those points. When disabled, the volumetrics will evaluate the lighting at regular intervals using many steps along each camera ray, and thus each pixel will take much longer to render, but when it's finished, it will have no noise at all. Enabling Use Probabilistic Shading is particularly useful when using the Progressive Image Sampler in V-Ray, as well as when using complex lighting on the volume.

Samples | prob_samples – Specifies the number of probabilistic samples to use when Use Probabilistic Shading is enabled. For the best rendering performance, use a higher number of samples for transparent smoke, and lower number for dense smoke. A very high number of samples will converge to standard ray-marching.

GI Samples | prob_samples_gi – Specifies the number of probabilistic samples to use for GI rays. The number of samples depends on whether the volumetric has an emissive component. Brighter emission requires more samples, while pure smoke can work with fewer.