This page provides information about the V-Ray Gaussian Splat in Maya.
Overview
3D Gaussian Splatting is a method used to create a 3D scene from images or videos. It requires several pictures of an object, each taken from a different angle. With Gaussian Splatting, the images are blended 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.
Gaussian splats help you create a realistic environment for your scenes.
This feature is not yet available in V-Ray GPU.
UI Path: V-Ray menu > V-Ray Gaussian Splat
V-Ray shelf > V-Ray Gaussian Splat button
Gaussian Splat Usage
Used as Extended Environment
One use of Gaussian splats is to represent an environment, typically 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 Casts Shadows option should usually be disabled.
See the example below for more information.
On Other Matte Surfaces
To make the Gaussian Splats rendered as part of the background, i.e., visible on other matte objects even if they are behind them. This is achieved by enabling 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 typically is turned off, and the Casts 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 the examples below for more information.
Parameters
Disable – Turns off the Gaussian splats. This option also turns off the export of the Gaussian splats to a .vrscene.
File – Loads the Gaussian splats file. Currently, only .ply files are accepted.
Scale – Scales the Gaussian splats up and down.
Primary Visibility – Specifies whether the Gaussian splats should be visible to the camera.
Visible in Reflections – Specifies whether the Gaussian splats should be visible in reflections.
Visible in Refractions – Specifies whether the Gaussian splats should be visible in refractions.
Casts Shadows – Enable so Gaussian splats block shadows from lights. When disabled, the Gaussian splats become transparent to shadow and GI rays. It is recommended that this option be turned off when using the Gaussian splats as environment or individual objects.
Affect Matte Surfaces – Enable so Gaussian splats appear as part of the background on matte surfaces. It is recommended to enable this for Gaussian splats used as an environment and disable it for Gaussian splats used as individual objects.
Intensity – Increases or decreases the Color multiplier for the Gaussian splat.
Color – Specifies a filter color for the splat. By default, the Color is white, which does not affect the splat.
RGB Primaries – Specifies the color space of the data in the Gaussian splats file.
Default – Takes the current color correction that is set in Maya. That means it does not change the colors.
For the Gaussian Splat to be read as it was written, select the respective input color space - sRGB, ACEScg or Raw.
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.
Scale = 0.5
Scale = 1
Scale = 1.5
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.
Example: Visible in Reflections
The Visible in Reflections option controls if the Gaussian Splat object is reflected in other objects in the scene.
Example: Visible in Refractions
The Visible in Refractions option makes the Gaussian Splat object seen by other objects in the scene that exhibit refractive properties.
Example: Casts Shadows
This example shows how the pink flamingo can produce shadows when the Casts Shadows option is enabled, and doesn't block light when it's not.
Example: Affect Matte Surfaces
In this example, the Gaussian Splat is used as an environment. The left building in the rendering that casts 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.
Example: Color
The Color shown on each render as a box is used as a filter for the original Gaussian Splat diffuse color.
Viewport
Preview Type – Specifies how the Gaussian splats are rendered in the viewport.
None – The Gaussian splats are not visible in the viewport and cannot be selected from there. You can select them from the Outliner only.
Bounding Box – The Gaussian splats are represented by a bounding box.
Point Cloud – This is the default mode. The Gaussian splats are represented by cloud points in a bounding box.
Viewport Primitives % – Determines what percent of the cloud points are visible in the viewport. This option works when the Preview Type is set to Point Cloud.
Preview Primitives Limit – Determines the exact number of points to be visible in the viewport. This option works when the Preview Type is set to Point Cloud.
Notes
- Gaussian splats work in V-Ray by assuming they are composed over a black background. For proper rendering, the scene background should be black and any dome lights used for illumination should be set to invisible.
- While you can load multiple Gaussian splat files and they are rendered correctly with respect to one another depending on their position in space, intersecting Gaussian splats might produce undefined or wrong results. It is not recommended to intersect them, as by designed they are optimized for a single point cloud.