Voxel Probe

Voxel Probe is a light source which provides static voxel lighting and shading on an object inside the probe by using a prebaked 3D lighting map. Unlike Environment Probe, Voxel Probe provides physically accurate light spreading inside interiors and outdoor static scenes but supports diffuse reflections only.

Also, Voxel Probe is great solution for shading dynamic objects within static areas.

Overview

Voxel Probe provides box volume compound of voxels and contains parameters used for light baking inside it.

Voxel Probe projects a 3D lighting texture on objects inside it thus providing an indirect light modelling. The texture should have an appropriate resolution which is calculated the following way:

Resolution = Width × Height × (Depth × 6)

Each pixel of a texture defines the illuminance of a certain voxel face.

An example of a 3D lighting texture

Voxel Probe is a required object for the Bake Lighting feature, which enables you to generate a lighting texture for the probe and simulate global illumination with indirect lighting for both, interiors and outdoor scenes.

Notice

By default Voxel Probes are used for lighting only, as for reflectons, it is recommended to simulate them using Environment Probes. This approach ensures the best result, however you can still enable reflections for a Voxel Probe.

Adding Voxel Probe

To add a Voxel Probe object to the scene via UnigineEditor, do the following:

On the Menu bar, click Create -> Light -> Voxel Probe.
Place the probe somewhere in the world.
Bake Lighting or set the Texture parameter by choosing a prebaked lighting texture from assets.

Voxel Probe Settings

Parameters of the voxel probe light are available in the Voxel Probe tab of the Parameters window. It includes both the common and the specific parameters. A set of specific ones is described below.

Common Parameters

Box Size	Specifies the size of the box volume.
Voxel Size	Sets the size of a voxel. Notice If the Box Size is not divisible to the Voxel Size without remainder, the voxel probe uses the lowest volume of voxels covering the box.

NoticeThese two parameters define the resolution of the voxel probe. Note that the memory usage is cubically dependent on the resolution, double growth of the voxel size causes eight-times growth of the size of the lighting texture.

Render Parameters

Additive Blending	Enables the additive blending mode for the voxel probe. This option offers more flexibility in lighting control. You can use it to blend lighting of several voxel probes together and control them separately (e.g. make a separate voxel probe for an indoor emissive light source and blend it with another voxel probe with lighting baked from the sky, having the ability to enable and disable them separately). Notice Voxel probes with additive blending enabled cannot be used as insets to add lighting details (e.g. creating a small high-detail voxel probe inside a large low-detail one). Such probes do not replace each other, as they are blended instead.
Use Sun Color	Enables the influence of sun light color on the voxel probe. When enabled, this option makes the voxel probe color black at night, or orange at sunset. Notice To bake lighting from the sky separately with this option enabled, it is recommended to enable baking visibility for the sky only, while disabling it for other light sources. Changing this option requires the lighting to be re-baked.

Additive Blending

Enables the additive blending mode for the voxel probe. This option offers more flexibility in lighting control. You can use it to blend lighting of several voxel probes together and control them separately (e.g. make a separate voxel probe for an indoor emissive light source and blend it with another voxel probe with lighting baked from the sky, having the ability to enable and disable them separately).

NoticeVoxel probes with additive blending enabled cannot be used as insets to add lighting details (e.g. creating a small high-detail voxel probe inside a large low-detail one). Such probes do not replace each other, as they are blended instead.

Use Sun Color

Enables the influence of sun light color on the voxel probe. When enabled, this option makes the voxel probe color black at night, or orange at sunset.

Notice

To bake lighting from the sky separately with this option enabled, it is recommended to enable baking visibility for the sky only, while disabling it for other light sources.

Changing this option requires the lighting to be re-baked.

Ambient Parameters

Color	Sets the color of ambient lighting.
Intensity	Sets the intensity of ambient lighting. Notice This parameter is used for manual adjustment in case if resulting intensity is too high or insufficient.
Bias	Sets the bias of ambient lighting by adjusting the voxels offset for fine tuning.
Cubic Filtering	Enables the cubic filtering of ambient lighting. Notice When disabled, the linear filtering is used.

Reflections Parameters

Enabled	Enables reflections for the Voxel Probe. By default Voxel Probes are used for lighting only, as for reflectons, it is recommended to simulate them using Environment Probes. This approach ensures the best result, however you can still enable reflections for a Voxel Probe via this option.
Color	Sets the color of the reflection.
Intensity	Sets the intensity of voxel probe's reflection. 0 value means no reflection. Notice This parameter is used for manual adjustment in case if resulting intensity is too high or insufficient.
Visibility Roughness Min	Sets the lower bound of the roughness range within which the reflections of the voxel probe are visible.
Visibility Roughness Max	Sets the higher bound of the roughness range within which the reflections of the voxel probe are visible. Notice The roughness range helps to choose between diffuse reflection of the voxel probe and other ones (reflection from an environment probe, the environment cubemap) for all materials having the Roughness parameter.
Bias	Sets the bias of reflection by adjusting the voxels offset for fine tuning.
Cubic Filtering	Enables the cubic filtering of reflection. Notice When disabled, the linear filtering is used.

Baking Settings

Notice
				The following parameters describe the way the light shall be baked inside the probe, so you need to re-bake lighting, when you make changes to these parameters.
			

Baking Viewport Mask	Sets the baking viewport mask which specifies the surfaces to be baked basing on their material's Viewport Mask.
Sampling Resolution	Sets the sampling resolution of the voxel probe.
Sampling Mip Offset	Sets the sampling mip offset of the voxel probe.
Num Rays	Sets the number of rays casted for each sample during light baking.
Near Clipping	Sets the distance to the near clipping plane used for every voxel during light baking.
Far Clipping	Sets the distance to the far clipping plane used for every voxel during light baking.
Fix Light Bleeding Intensity	Sets the intensity of light bleeding correction, which provides fine control over color intensity of the emitted light: The minimum value of 0 corresponds to disabled correction. The maximum value of 1 equals maximum correction.
Fix Light Bleeding Radius	Sets the distance on which light bleeding is fixed.
Fix Light Bleeding Bounce	Enables light bleeding correction of Voxel Probe.
Bake Internal Volume	Enables internal volume baking of Voxel Probe. Enabled option corresponds to baking all voxels of the probe. Disabled option equals baking the voxels that cover geometry and skipping the empty ones. Notice Having baked internal volume makes it possible to realistically shade dynamic objects that move inside the voxel probe as the lighting texture is projected onto all the geometry. If the option is disabled, the lighting is interpolated between neighboring voxels.
Full Resolution Bounces	Enables calculation of bounces at full resolution. Defines whether indirect light bounces are computed at the same full resolution as the last one or the resolution should increase from the lowest to full with each bounce iteration.
Caustic	Enables caustics calculation for the voxel probe. Notice It is recommended to increase sampling resolution and number of rays when enabling this option. Enabling caustics calculation may result in increased noise.
Notice You can use the following 7 visibility options together with additive blending to provide more flexibility in light baking. Thus, you can make voxel probes independent of each other and combine them to produce some sort of dynamic GI effect.
Visibility Emission	Enables baking of emission light sources to the voxel probe.
Visibility Sky	Enables baking of lighting from the sky to the voxel probe.
Visibility Light World	Enables baking of world light sources to the voxel probe.
Visibility Light Omni	Enables baking of omni light sources to the voxel probe.
Visibility Light Proj	Enables baking of projected light sources to the voxel probe.
Visibility Voxel Probe	Enables baking of other voxel probe light sources to the voxel probe.
Visibility Environment Probe	Enables baking of environment probe light sources to the voxel probe.
Texture	Sets the 3D lighting texture. Notice Every bake lighting procedure makes changes to the asset which is set for this parameter. You can leave the field empty to avoid losing content. In this case a new generated lighting texture will be set for this parameter after the bake lighting procedure. Generated textures are stored in the data/bake_lighting folder.

Last update: 10.08.2018

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