Unity Add-on

Version

Release 0.5.0 — June 05 2025

About

With this package, users can:

• Enter text prompts to generate 3D Gaussian Splats (3DGS) and mesh FBX models

• Display 3D Gaussian Splats inside Unity

• Apply cutouts, colliders, and shadows to 3D Gaussian Splats

• Import and export .ply files

• Convert 3DGS to mesh

Installation

Software requirements

Unity 2022.3+

Instructions

1. From the Unity Asset Store, click "Add to My Assets"

2. Download the Package

• In Unity, create a new 3D project or open an existing one

• Go to My Assets

• Select 404—GEN from the list

• Click "Download"

3. Import the Package

• After the package has been downloaded, click "Import"

• When the import window appears, keep all files selected and click "Import"

4. Edit Project Settings

• Go to Edit > Project Settings... > Player > Other Settings

• Make sure that the correct rendering backend is selected

  • Direct3D12 on Windows

  • Metal on Mac

  • Vulkan on Linux

Universal Render Pipeline (URP) and High Definition Render Pipeline (HDRP)

As Unity's URP and HDRP are more complex than the Built-in Render Pipeline, a Gaussian Splat render pass must be added to the scene in order to generate Gaussian Splats.

This step is not necessary when only generating mesh.

When the custom render pass is not present, the 404—GEN 3D Generator window will display a warning message, along with a button to Load URP/HDRP support pack, then Add custom rendering pass.

Usage

Generating

1. Go to Window > 404-GEN 3D Generator to open the generation window

2. Select Gaussian Splat or mesh model.

3. Type your prompt and click Generate. Each generation should take approximately one to two minutes.

Prompts

For help structuring prompts, visit the Prompts section of this guide:

Transformations

In addition to the Position, Rotation, and Scale values in the Inspector, there are two easily adjustable values.

• Splat Scale: Controls the size of the points, represented by ellipsoids, in the Gaussian Splat

• Opacity Scale: Points within Gaussian Splats have varying degrees of opacity. This increases or decreases the opacity of all points.

Cutouts

The cutouts feature can be used to hide a selection of points within the Gaussian Splat, defined by either a box or ellipsoid.

Create a cutout for a selected Gaussian Splat by clicking Add Cutout under the Cutouts heading of the Inspector.

Select a shape and move/scale/rotate as needed.

By default, only the points inside the cutout will be rendered. Select invert to render the points outside the cutout.

Mesh Collider

The Add Mesh Collider button in the Inspector will add a convex hull mesh collider.

Shadows

Like the mesh collider, the Add Shadow button in the inspector adds an invisible convex hull mesh to the Gaussian Splat. The shadow it casts lacks any fine details, however the convex hull's low poly count makes it very lightweight.

Convert to Mesh

The Convert to Mesh button will open a Mesh Conversion window with input field (for Gaussian Splat component), file output folder location, conversion settings, reference fields for files that are created in the process (.ply and .mesh files), as well as the reference field for the game object that will be created and placed in current scene (Instance).

The sliders adjust the level of detail on the mesh output.

Once the Start conversion to Mesh button is used the process will start populating the object fields as they are created. The process takes approximately one minute to convert the Gaussian Splat (PLY) to mesh (FBX).

Import/Export .ply

The Gaussian Splat can be exported in .ply format using the Export PLY button.

.ply files can be imported by adding them to the project's Assets folder and the scene.

A large collection of Gaussian Splatting .ply files is available in the 404 Dataset.

Gaussian Splats

To learn more about 3DGS (3D Gaussian Splatting), visit the Gaussian Splatting section of this guide: