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Overview

Procedural Volumetric Cloud is the feature to render dynamic clouds for large scale outdoor environments. Clouds are procedurally generated by combination of noise function and volume texture artists create. After that clouds are rendered by using ray-marching and physically plausible shading.


Usage

This feature is turned off by default. Before using this, you need to set the CVar r_VolumetricClouds=1 or 2 in the console window or by adding it to the system.cfg or game.cfg to activate this feature. If nothing shows, please see the CVar e_Clouds is set to 1.

After it's activated, you can adjust the parameters for Procedural Volumetric Clouds in Environment Editor and Level Settings.

Following parameters affects the final appearance of clouds.

  • Environment Editor
    • Sun
    • Sky Light
    • Cloud Shading
    • Volumetric Clouds
  • Level Settings
    • Env State
      • Wind Vector (the wind moves clouds.)
    • Volumetric Cloud

VolumetricCloudSwitch Flowgraph node

VolumetericCloudSwitch was added to Environment Flowgraph node group.

Using this node, you can switch user-defined volumetric cloud texture, tiling size, and tiling offset at run-time.

CloudBlocker entity

This entity can exclude or decay clouds inside or outside of a sphere region.

Up to 4 entities in a level can work simultaneously.

ParameterDescription
ActiveIf true, cloud blocker will be activated.
DecayEndSpecifies the end distance of fog density decay. (in meters)
DecayStartSpecifies the start distance of cloud density decay. (in meters)
DecayInfluenceSpecifies the influence of fog density decay.

CVars

Cvar
Description
Comment and examples
r_VolumetricCloudsEnables procedural volumetric clouds.

0 - Disabled (default)

1 - Enabled (1/2x Resolution)

2 - Enabled (1/4x Resolution)

r_VolumetricCloudsRaymarchStepNum

Set the step number of ray-marching for procedural volumetric clouds.

Acceptable number is from 16 to 256, and it should be multiple of 16.

64 (default)
r_VolumetricCloudsPipelineSet the pipeline mode of procedural volumetric clouds.

0 - Monolithic shader pipeline, using less memory.

1 - Multiple shaders pipeline, using more memory, mostly faster.(default)

r_VolumetricCloudsStereoReprojectionEnables stereoscopic reprojection for procedural volumetric clouds to accelerate the rendering.

0 - Disabled.

1 - Enabled. (default)

r_VolumetricCloudsTemporalReprojectionSet temporal reprojection mode for procedural volumetric clouds.

0 - faster but prone to flickering artifacts.

1 - a bit slower but less flickering artifacts. (default)

r_VolumetricCloudsShadowResolutionSet the resolution of volumetric clouds shadow map for casting shadow on the terrain and low shading-LOD clouds.64 (default)
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