unreal.MaterialExpressionVolumetricAdvancedMaterialOutput

class unreal.MaterialExpressionVolumetricAdvancedMaterialOutput(outer: Object | None = None, name: Name | str = 'None')

Bases: MaterialExpressionCustomOutput

Material output expression for writing advanced volumetric material properties.

C++ Source:

  • Module: Engine

  • File: MaterialExpressionVolumetricAdvancedMaterialOutput.h

Editor Properties: (see get_editor_property/set_editor_property)

  • clamp_multi_scattering_contribution (bool): [Read-Write] Set whether multiple scattering contribution entry is clamped in [0,1] or not. When disabled, the artist is in charge for ensuring the visual remain in a reasonable brighness range.

  • const_multi_scattering_contribution (float): [Read-Write] Only used if MultiScatteringContribution is not hooked up. Multi-scattering approximation: represents how much contribution each successive octave will add. Valid range is [0,1], from low to high contribution

  • const_multi_scattering_eccentricity (float): [Read-Write] Only used if MultiScatteringEccentricity is not hooked up. Multi-scattering approximation: represents how much the phase will become isotropic for each successive octave. Valid range is [0,1], from anisotropic to isotropic phase.

  • const_multi_scattering_occlusion (float): [Read-Write] Only used if MultiScatteringOcclusion is not hooked up. Multi-scattering approximation: represents how much occlusion will be reduced for each successive octave. Valid range is [0,1], from low to high occlusion.

  • const_phase_blend (float): [Read-Write] Only used if PhaseBlend is not hooked up. Lerp factor when blending the two phase functions parameterized by G and G2. Valid range is [0,1].

  • const_phase_g (float): [Read-Write] Only used if PhaseG is not hooked up. Parameter ‘g’ input to the phase function describing how much forward(g<0) or backward (g>0) light scatter around.

  • const_phase_g2 (float): [Read-Write] Only used if PhaseG2 is not hooked up. Parameter ‘g’ input to the second phase function describing how much forward(g<0) or backward (g>0) light scatter around. Valid range is [-1,1].

  • desc (str): [Read-Write] A description that level designers can add (shows in the material editor UI).

  • gray_scale_material (bool): [Read-Write] Set this for the material to only be considered grey scale, only using the R chanel of the input parameters internally. The lighting will still be colored. This is an optimisation.

  • ground_contribution (bool): [Read-Write] Sample the shadowed lighting contribution from the ground onto the medium (single scattering). This adds some costs to the tracing when enabled.

  • material_expression_editor_x (int32): [Read-Write]

  • material_expression_editor_y (int32): [Read-Write]

  • multi_scattering_approximation_octave_count (uint32): [Read-Write] How many octave to use for the multiple-scattering approximation. This makes the shader more expensive so you should only use 0 or 1 for better performance, and tweak multiple scattering parameters accordingly. 0 means single scattering only. The maximum value is 2 (expenssive).

  • per_sample_phase_evaluation (bool): [Read-Write] Set this to true to force the phase function to be evaluated per sample, instead once per pixel (globally). Per sample evaluation is slower.

  • ray_march_volume_shadow (bool): [Read-Write] Disable this to use the cloud shadow map instead of secondary raymarching. This is usually enough for clouds viewed from the ground and it result in a performance boost. Shadow now have infinite length but also becomes less accurate and gray scale.