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This page provides information on the V-Ray Gaussian splatting models.



Overview


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3D Gaussian Splatting is a method used to create a 3D scene from images or videos. It requires several different pictures of an object, each taken from a different angle. With Gaussian Splatting, the images are blended together to produce a detailed, three-dimensional representation of the object. Instead of depicting the scene as a collection of meshes, a Gaussian splat represents the scene as a type of point cloud, where each point is a 3D Gaussian.


||Command panel|| > Create tab > Geometry > V-Ray category > VRayGaussiansGeom button

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Gaussian Splat Usage



Used as Extended Environment

One use of Gaussian splats is to represent an environment generated from photos or videos of the scene.

There are advantages over the traditional environment maps, including proper parallax and view-dependent effects and the ability for Gaussian splats to occlude other objects in the scene.

For Gaussian splats to work as environments in V-Ray, the Affect matte surfaces option should be enabled, and the Affect shadows option should usually be disabled.

See the example below for more information.

On Other Matte Surfaces

To render the Gaussian Splats as part of the background, i.e., visible on other matte objects even if they are behind them, enable the Affect matte surfaces option from the Gaussian splats parameters.

See the example below for more information.

As Matte Objects

Gaussian splats can also function as holdout (matte) objects, i.e. appear correctly in reflections and refractions and occlude other objects in the scene but do not contribute to the RGB and alpha channels of the final image.

This can be achieved by enabling the Matte Surface option in the V-Ray Object Properties of a Gaussian splats object and setting its Alpha Contribution to -1.0. Make sure that No GI on Other Mattes is enabled.

Used as Individual Objects

Gaussian splats can also be used to represent smaller individual objects in the scene. In that case, the Affect matte surfaces option is turned off, and the Affect shadows option is enabled. The latter is needed so that the Gaussian splats can cast proper shadows on other objects in the scene.

Note that the lighting and reflections are baked into the Gaussian splats object, and therefore these objects are not affected by the scene lighting.

See theexamples below for more information.



Parameters


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File – Specifies a .ply file.

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The VRayGaussianGeom works only with Gaussian .ply files.

Flip axis – Flips the axis, which is a rotation to -90 degrees around the X axis.

Scale – Allows the Gaussian splat to be scaled up or down.

Affect camera – Specifies if the Gaussian splat is visible to camera rays.

Affect shadows – Specifies if the Gaussian splat affects shadow rays.

Affect reflections – Specifies whether the Gaussian splat is rendered in reflections.

Affect refractions – Specifies whether the Gaussian splat is rendered in refractions.

Affect matte surfaces – Computes Gaussian splats behind matte objects as part of the background.

RGB Primaries – Specifies the color space of the Gaussian splat's data.

Intensity – Multiplies the Color parameter. Increasing the value boosts the effect.

Color – Specifies the main color tint for the Gaussian splat - white color makes no changes.

Viewport primitives – Determines the maximum number of primitives displayed in the viewport.

Show box – Displays a bounding box in the viewport.

Select points – When this option is off (default), click on the box or the splat name in the viewport to select the splat. When it is on, click directly on the point cloud in the viewport to select the splat.

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Example: Scale

This example shows Gaussian Splat used as an individual object - the pink flamingo floatable in this scene. It can be scaled as any other object in the scene, using the Scale parameter.

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Scale = 0.5

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Scale = 1

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Scale = 1.5

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Example: Primary Visibility

The Gaussian Splat object can be hidden from camera, like any other geometry object in the scene by using the Primary Visibility option.


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Example: Affect reflections

The Affect reflections option controls if the Gaussian Splat object is reflected in other objects in the scene.


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Example: Affect refractions

The Affect refractions option makes the Gaussian Splat object seen by other objects in the scene that exhibit refractive properties.


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Example: Affect shadows

This example shows how the pink flamingo can produce shadows when the Affect shadows option is enabled and doesn't block light when it's not.


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Example: Affect matte surfaces

In this example, the Gaussian Splat is used as an environment. The left building in the rendering that Affect shadows over the plane, is a Cosmos asset (mesh).

When Affect matte surfaces option is enabled, the Gaussian Splat is considered as background and receives shadows from the casting object.


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Example: Color

The Color shown on each render as a box is used as a filter for the original Gaussian Splat diffuse color.

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