This page provides information about the V-Ray Gaussian Splat.
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.
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 Visible in Matte Surfaces option should be enabled, and the Casts Shadows option should usually be disabled.
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 Visible in Matte Surfaces option from the Gaussian splats parameters.
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 Visible in 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.
Parameters
Main
File (.ply) – Loads the Gaussian splats file. Currently, only .ply files are accepted.
Color Space – 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.
Flip Axis – Controls which axis is used as a vertical - the Y or Z axes for the loaded file. You can choose between:
As Is – No changes in the axes are applied.
Rotate YZ– Switches the Y and Z axes.
Rotate XZ + Flip Y – Switches the X and Z axes and flips the Y axis.
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. See the Color example below.
Affect Camera – Specifies whether the Gaussian splats should be visible to the camera. See the Affect Camera example below.
Visible in Reflections – Specifies whether the Gaussian splats should be visible in reflections. See the Visible in Reflections example below.
Visible in Refractions – Specifies whether the Gaussian splats should be visible in refractions. See the Visible in Refractions example below.
Visible in 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. See the Visible in Matte Surfaces example below.
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. See the Cast Shadows example below.
Preview
Preview Type – Specifies how the Gaussian splats are rendered in the viewport.
Placeholder – The Gaussian splats are not visible in the viewport and cannot be selected from there.
Bounding Box – The Gaussian splats are represented by a bounding box. This is the default mode.
Preview Geometry – The Gaussian splats are represented by cloud points.
Max Preview Points – Controls how many points are shown in the preview.
Example: Affect Camera
The Gaussian Splat object can be hidden from camera, like any other geometry object in the scene by using the Affect Camera 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: Visible in 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 Visible in 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.
