Procedural Volumetric Clouds
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 (Old as of 26/2) 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
- Env State
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.
| Parameter | Description |
|---|---|
| Active | If true, cloud blocker will be activated. |
| DecayEnd | Specifies the end distance of fog density decay. (in meters) |
| DecayStart | Specifies the start distance of cloud density decay. (in meters) |
| DecayInfluence | Specifies the influence of fog density decay. |
CVars
Cvar | Description | Comment and examples |
|---|---|---|
| r_VolumetricClouds | Enables 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_VolumetricCloudsPipeline | Set 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_VolumetricCloudsStereoReprojection | Enables stereoscopic reprojection for procedural volumetric clouds to accelerate the rendering. | 0 - Disabled. 1 - Enabled. (default) |
| r_VolumetricCloudsTemporalReprojection | Set temporal reprojection mode for procedural volumetric clouds. | 0 - faster but prone to flickering artifacts. 1 - a bit slower but less flickering artifacts. (default) |
| r_VolumetricCloudsShadowResolution | Set the resolution of volumetric clouds shadow map for casting shadow on the terrain and low shading-LOD clouds. | 64 (default) |