# Fog

#### new Cesium.Fog()
engine/Source/Scene/Fog.js 16

Blends the atmosphere to geometry far from the camera for horizon views. Allows for additional performance improvements by rendering less geometry and dispatching less terrain requests.

##### Demo:

- Cesium Sandcastle Fog Demo

### Members

#### density : number
engine/Source/Scene/Fog.js 49

A scalar that determines the density of the fog. Terrain that is in full fog are culled. The density of the fog increases as this number approaches 1.0 and becomes less dense as it approaches zero. The more dense the fog is, the more aggressively the terrain is culled. For example, if the camera is a height of 1000.0m above the ellipsoid, increasing the value to 3.0e-3 will cause many tiles close to the viewer be culled. Decreasing the value will push the fog further from the viewer, but decrease performance as more of the terrain is rendered.

Default Value: `0.0006`

##### Example:

    // Double the default fog density
    viewer.scene.fog.density = 0.0012;

#### enabled : boolean
engine/Source/Scene/Fog.js 25

`true` if fog is enabled, `false` otherwise.

Default Value: `true`

##### Example:

    // Disable fog in the scene
    viewer.scene.fog.enabled = false;

#### heightFalloff : number
engine/Source/Scene/Fog.js 100

Exponent factor used in the function to adjust how density changes based on the height of the camera above the ellipsoid. Smaller values produce a more gradual transition as camera height increases. Value must be greater than 0.

Default Value: `0.59`

#### heightScalar : number
engine/Source/Scene/Fog.js 55

A scalar used in the function to adjust density based on the height of the camera above the terrain.

Default Value: `0.001`

#### maxHeight : number
engine/Source/Scene/Fog.js 62

The maximum height fog is applied. If the camera is above this height fog will be disabled.

Default Value: `800000.0`

#### minimumBrightness : number
engine/Source/Scene/Fog.js 89

The minimum brightness of the fog color from lighting. A value of 0.0 can cause the fog to be completely black. A value of 1.0 will not affect the brightness at all.

Default Value: `0.03`

#### renderable : boolean
engine/Source/Scene/Fog.js 36

`true` if fog is renderable in shaders, `false` otherwise. This allows to benefits from optimized tile loading strategy based on fog density without the actual visual rendering.

Default Value: `true`

##### Example:

    // Use fog culling but don't render it
    viewer.scene.fog.enabled = true;
    viewer.scene.fog.renderable = false;

#### screenSpaceErrorFactor : number
engine/Source/Scene/Fog.js 82

A factor used to increase the screen space error of terrain tiles when they are partially in fog. The effect is to reduce the number of terrain tiles requested for rendering. If set to zero, the feature will be disabled. If the value is increased for mountainous regions, less tiles will need to be requested, but the terrain meshes near the horizon may be a noticeably lower resolution. If the value is increased in a relatively flat area, there will be little noticeable change on the horizon.

Default Value: `2.0`

#### visualDensityScalar : number
engine/Source/Scene/Fog.js 73

A scalar that impacts the visual density of fog. This value does not impact the culling of terrain. Use in combination with the `Fog.density` to make fog appear more or less dense.

Default Value: `0.15`

##### Example:

    // Increase fog appearance effect
    viewer.scene.fog.visualDensityScalar = 0.6;

##### Experimental

The value of this scalar may not be final and is subject to change.

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