The Gaussian Splat shape renders point-based scene representations composed of millions of oriented volumetric splats instead of traditional polygonal geometry. Gaussian splats are commonly generated from photogrammetry, neural rendering, or radiance field reconstruction workflows and provide an efficient way to represent highly detailed real-world captures.

Each splat is represented as an anisotropic 3D Gaussian distribution defined by:

• Position — center of the splat in 3D space
• Scale — ellipsoid size along each axis
• Orientation — rotation of the ellipsoid
• Color / Radiance — emitted or reflected appearance
• Opacity — transparency contribution

During rendering, Arnold projects and blends splats together to reconstruct continuous surfaces and volumetric detail with smooth transitions and high visual fidelity.

The Gaussian Splat shape loads and renders Gaussian splat datasets inside Arnold. These parameters control file loading, viewport display, color handling, and advanced rendering options.

Path (PLY)

Specifies the Gaussian Splat file to load (PLY).

Min Pixel Width

Defines the minimum on-screen size of individual splats in pixels. Increasing the Min Pixel Width (MPW) can help reduce holes and sparse regions, improve the visibility of distant splats, and produce smoother surface reconstructions. Lower values preserve finer detail but may introduce gaps or aliasing in thin regions.

For best results, use an MPW value close to 1.0. Setting MPW too low may cause visible holes or missing coverage.

Invert X / Invert Y / Invert Z

Inverts the splat positions and orientations along the corresponding axis. Useful for correcting datasets that were exported from tools using a different coordinate-system convention than Cinema 4D.

Scale

Applies a uniform scale to the loaded splat data. The adjacent unit dropdown specifies the unit (e.g. Meters) used to interpret the values stored in the source file.

Shading

Controls how each splat's stored color and radiance data is interpreted, shaded, and combined into the final image.

Diffuse Weight

Scales the diffuse shading contribution from scene lights. Use a non-zero value to have splats respond to Arnold lights; set to 0.0 for an unshaded, radiance-only look.

Note that the fish in the example below is a polygon mesh. This demonstrates that Gaussian splats can be mixed with meshes, curves, and volumes in the same scene, while still supporting ray-traced effects such as reflections and refractions.

Diffuse Tint

Applies a color multiplier to the diffuse component of each splat.

Diffuse Roughness

Controls the roughness of the diffuse response. Higher values produce a flatter, more uniform diffuse falloff across each splat.

Emission Weight

Scales the contribution of each splat's stored radiance, treating splat color as emitted light. A value of 1.0 renders splats at their captured brightness; 0.0 disables the emission contribution.

Emission Tint

Applies a color multiplier to the emission component of each splat. White preserves the original captured color; other values shift the emitted appearance for look development, grading, or matching scene lighting.

Color Space

Specifies the color space used to interpret splat color data. Choose the color space that matches the source dataset to ensure accurate shading and lighting.

Visibility

Controls which ray types the Gaussian splat object is visible to.

Camera (Primary)

Splats are visible to primary camera rays.

Shadow

Splats cast shadows from light sources.

Diffuse Reflection

Splats are visible to diffuse reflection rays.

Diffuse Transmission

Splats are visible to diffuse transmission rays.

Specular Reflection

Splats are visible to specular reflection rays.

Specular Transmission

Splats are visible to specular transmission rays.

Volume Scattering

Splats are visible to volume scattering rays.

Self Shadows

Enables the Gaussian splat object to cast shadows onto itself.

Opaque

Marks the splats as fully opaque, which improves rendering performance by skipping transparency evaluation. Disable when the dataset requires accurate transparency.

Matte

Turns the object into a holdout matte. The splats become invisible in the final image but still occlude objects behind them, useful for compositing.

Trace Sets

Assigns the splats to one or more trace sets, allowing shaders and lights to include or exclude this object via trace set membership.