Lumberyard
User Guide (Version 1.16)

Fog Volume

This feature is in preview release and is subject to change.

You can use the Fog Volume component to create fog effects in your game. For more information, see Volumetric Fog.

By default, the Fog Volume component renders in nonvolumetric mode. To enable volumetric rendering, you must specify the e_VolumetricFog console variable. For more information, see Console Variables for Volumetric Fog and Using the Console Window.

Note

The Fog Volume component must have a Box Shape component attached to the entity. The entity uses the Box Shape component to set the area of the fog.

You can also change global fog properties in the Time of Day editor. For more information, see Setting Global (Time of Day) Fog.


            Fog Volume component example.

Fog Volume Properties

The Fog Volume component has the following properties:

Volume type

Specify the volume shape, which can be an ellipsoid or cuboid. A Box Shape component attached to the entity defines the boundaries for both shapes.

Color

Color of the fog. Specify a color with the Color Picker.

Default: 255, 255, 255

HDR Dynamic (Nonvolumetric fog only)

Specify the brightness of the fog color.

Default: 0

Valid values: 020

Use global fog color

If true, the Color property is ignored, and the global fog color is used instead. In the Time of Day editor, you can specify the global fog color with the Color (bottom) parameter. For more information, see Setting Global (Time of Day) Fog.

Default: False

Soft edges

Specify a factor to soften the edges of the fog volume. When you view the fog volume, the fog gradually fades into the surrounding area.

Default: 1

Valid values: 0 to 1

Wind influence (Volumetric fog only)

Specify the influence that the global wind has on the fog volume.

Default: 1

Valid values: 0 to 20

Fog Density

Specify the density of the fog volume.

Default: 1

Valid values: 0 to 1000

Density offset

Specify the offset of the density of the fog volume. Specify higher values to reduce fog density around the edges.

Default: 0

Valid values: -1000 to 1000

Near cutoff

Stops rendering the fog volume, depending on the camera distance from the object, in meters.

Default: 0

Valid values: 0 to 2

Rendering General

The Fog Volume component has the following rendering options:

Minimum spec

Minimum specifications for the fog volume to be active.

Default: Low

View distance multiplier

Adjusts the maximum view distance.

Default: 1

Valid values: 0 to ∞ (infinity)

Ignore vis. areas

Specify whether the Fog Volume component affects visible areas and clip volumes. If true, the fog volume does not affect visible areas and clip volumes.

Default: False

Affect this area only

Specify whether the Fog Volume component affects only the specified area. If false, the Fog Volume component can affect multiple visible areas and clip volumes.

Default: False

Fall Off Settings

The Fog Volume component has the following fall off settings:

Longitude

Direction of the fall off or where the fog starts to fade in the world space. Specify a value of 0 so that the fog starts to fade on the east side of the Fog Volume component.

Default: 0

Valid values: 0 to 360

Latitude

Direction of the fall off or where the fog starts to fade in the world space. Specify a value of 90 so that the fog starts to fade on top of the Fog Volume component.

For more information, see Volumetric Fog Examples.

Default: 90

Valid values: 0 to 360

Shift

Specify how much to move the fog density along the fall-off direction. Specify a positive value to move thicker fog layers along the fall off direction of the fog volume. Specify a negative value to move thicker layers along the opposite direction.

Default: 0

Valid values: -5050

Scale

Scales the density distribution along the fall-off direction. Specify higher values to make the fog fall off more rapidly.

Default: 1

Valid values: -50 to 50

Ramp (Volumetric Fog Only)

The Fog Volume component has the following ramp options:

Start

Specify the start distance of the fog density ramp, in meters.

Default: 1

Valid values: 0 to 30000

End

Specify the end distance of the fog density ramp, in meters.

Default: 50

Valid values: 0 to 30000

Influence

Specify the influence of the fog density ramp.

Default: 0

Valid values: 0 to 1

Density Noise (Volumetric Fog Only)

The Fog Volume component has the following density noise options:

Scale

Specify the noise value for the fog volume density. This parameter defines the thickness of the individual patches of fog. Specify a low value to thin out the fog density and increase the space between patches of fog.

Default: 1

Valid values: 0 to 10

Offset

Offsets the noise value for the density. Specify a value to break the solid shape of the fog volume into patches.

Default: 1

Valid values: -2 to 2

Time frequency

Specify the time frequency of the noise for the density. Specify high frequencies to create fog that changes quickly. You can use this parameter to cause the individual fog patches to morph into different shapes over the course of their lifetime.

Note

As a best practice, specify a low value. High values can cause the fog to morph too quickly.

Default: 0

Valid values: 0 to 1

Spatial frequency

Specify the spatial frequency of the noise for the density. You can use this parameter to define the amount of patchy fog in the fog volume. You can increase the z-value to create a layered effect in the volume; this stacks fog patches on top of each other. Specify higher x- and y-values to create more individual fog patches within the volume.

Default: 10, 10, 10

Light Component Fog Properties

If you add light components to your entities, you can also specify following parameters for light components:

Volumetric Fog

Enables the light to affect volumetric fog.

Volumetric Fog Only

Enables the light to affect volumetric fog and not affect other objects, such as meshes.

Example

In the following example, the parameter Volumetric Fog On is enabled for the light component.


                        Fog Volume component and light component where
                            Volumetric Fog is enabled.

In the following example, the parameter Volumetric Fog is disabled for the light component.


                        Fog Volume component and light component where
                            Volumetric Fog is disabled.

For more information about light components, see Rendering.

Volumetric Fog Examples

In the following example, the value for Latitude is 0. The fall off appears on the left side of the fog volume, along the x-axis.


                    Fog Volume component example with fall off on one
                        side, or 0 degrees latitude.

In the following example, the value for the Latitude is 90. The fall off appears on the top for the fog volume.


                    Fog Volume component example fall off on the top of
                        the volume, or 90 degrees latitude.

Note

For the Fog Volume component, the Latitude and Longitude parameters work in the world space. Local transform changes do not affect these parameters. The Latitude and Longitude parameters orient the fog volume on the xy-plane. You can specify different values to orient the fog volume in any direction.