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KIRI 3DGS Render

📖5 min read
KIRI Engine: 3DGS Blender Addon Tutorial

Introduction​

The KIRI 3DGS Render addon brings the power of 3D Gaussian Splatting (3DGS) directly into Blender. It provides a complete workflow for importing, editing, and rendering 3DGS scans, which are typically difficult to handle in traditional 3D software.

It allows for real-time rendering of splats without heavy performance penalties and includes tools to convert standard Mesh objects into 3DGS representations.

Source Code

Access the source code on GitHub.

Official Site

Visit the KIRI Engine website.

Related Topics

Main Content Section​

Core Working Modes​

The addon offers three distinct modes to suit different stages of the 3DGS pipeline:

  1. Edit Mode (Legacy): Treats 3DGS files as mesh objects. This allows for standard mesh edits (modifiers, animation) but can be slower performance-wise. Ideally used for fine-tuning geometry.
  2. Render Mode: introduced in v4.0, this mode enables real-time and offline rendering of Gaussian Splats without the performance constraints of high-poly meshes.
  3. Mesh-2-3DGS: A powerful utility to convert standard .OBJ mesh models into 3DGS .PLY files, provided they have a texture and .MTL file.

Workflow & Performance Tips​

Working with Gaussian Splats involves handling millions of points, which can tax your system. The addon provides several tools to manage this:

  • Display as Point Cloud: In Edit Mode, it is highly recommended to display objects as Point Clouds (rather than fully updated faces) while moving objects or setting up cameras to maintain performance.
  • Camera Culling: A vital modifier that hides splats outside the camera's view or based on distance, significantly improving viewport responsiveness.
  • Orthographic View Warning: Faces cannot be updated correctly in orthographic view; ensure you are in a perspective view to avoid errors.
  • Proxy Objects: The Render Mode uses "Proxy Empties" to represent the location and rotation of the splats efficiently in real-time.

Key Features​

3DGS Editing & Modifiers​

The addon allows for destructive and non-destructive editing:

  • Decimate: Reduce the total number of faces/splats.
  • Crop Box: Remove splats inside or outside a defined volume.
  • Color Edit: Remove splats based on color thresholds (e.g., removing a blue sky).
  • Shadeless vs. Lit: Toggle between checking how the splats look with raw colors ("Shadeless") or reacting to Blender's scene lighting.

Rendering Capabilities​

  • Real-time Preview: View the splats with high-quality transparency sorting in the viewport.
  • Hybrid Rendering: "Combine With Native Render" allows compositing 3DGS scans with standard Blender mesh elements (like reference grids or reconstructed buildings) in the final image.
  • Animation Support: Render full animations of camera movements through the 3DGS scene.

Mesh-to-3DGS Conversion​

This feature allows you to "splat-ify" traditional models.

  • Requirements: A fully triangulated .OBJ file, a corresponding texture image (.JPG/.PNG), and a .MTL file.
  • Platform: Currently Windows only.

Requirements​

  • Blender Version: Made for Blender 4.5, but compatible with 4.3+.
  • Input: Only 3DGS .PLY files. Non-3DGS point clouds will cause errors.

Summary​

The KIRI 3DGS Render addon is a bridge between the specialized world of Gaussian Splatting and the versatile environment of Blender. Whether you need to render a captured environment for a case study or convert a standard model into a point-based representation, this addon provides the necessary toolset. Its dual-mode approach (Edit vs. Render) balances the need for precise manipulation with real-time performance.

Key Takeaways:

  • Imports and renders 3D Gaussian Splats (.ply) natively in Blender.
  • Dual modes optimize for either editing precision or rendering speed.
  • Includes tools to clean up noisy scans (Crop, Color Edit, Decimate).
  • Enables hybrid rendering of Splats and Mesh objects.

Documentation for Methodology​

What to document when using KIRI 3DGS Render

In Your Method Section​

When using this addon for visualising a scene, document:

  • Source Data: Origin of the .ply file (e.g., KIRI Engine app, Luma AI, etc.).
  • Cleanup Steps: Any modifiers used to clean the scan (e.g., "Crop Box used to isolate the vehicle," "Color Edit used to remove sky artifacts").
  • Render Settings: Whether "Shadeless" or "Lit" mode was used, and if "Combine With Native Render" was used to show spatial context.
  • Addon Version: e.g., v4.0+.

In Your Decision Log​

Record the following:

  • Why specific parts of the scan were removed (e.g., "Removed bystanders using Crop Box").
  • Any color adjustments made to improve visibility.
  • The choice between using the scan as a visual reference vs. a measurement source.

Verification​

  • Overlay the 3DGS render with original site photos or video frames to verify scale and orientation.
  • If using the Mesh-2-3DGS feature, compare the output .ply against the original .obj to ensure texture fidelity.

Common Limitations​

  • Transparency artifacts: "Cloudy" look if depth sorting fails (try adjusting view).
  • Lighting: 3DGS files often have baked-in lighting that may clash with Blender scene lights unless handled carefully.
  • Performance: Heavy scenes can be slow to update in "Face" mode; use Point Cloud mode for navigation.

Example Methodology Statement​

"The scene was visualized using the KIRI 3DGS Render addon in Blender 4.3. The raw 3DGS .ply file, captured via the KIRI Engine app, was imported and aligned to the ground plane. Noise and background artifacts were removed using the addon's 'Crop Box' and 'Decimate' modifiers. The final visualization was rendered using the 'Combine With Native Render' feature to composite the scan with a reference grid and witness camera markers."

Further Resources: