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3DGS Viewer

3DGS scene annotation

Annotate 3D Gaussian Splatting scenes with markers, areas, paths, and measurements

Use the free browser-based Scene Annotation tool to add semantic labels to 3D Gaussian Splatting models. Place point markers, draw area polygons, trace paths, and measure distances directly on the 3DGS surface. Export a single structured JSON file with embedded schema description, ready for digital twin pipelines and AI processing.

Place point, area, path, and measurement annotations precisely on 3DGS surfaces using WASM-accelerated raycasting.

Organize annotations with custom categories, custom properties, and parent-child hierarchy for complex scenes.

Export a self-documenting JSON file with embedded schema, annotations, viewpoints, and scene calibration data.

How to use this tool

  1. 1Upload a 3DGS model (PLY, SPZ, SPLAT, KSPLAT, or SOG) by dragging it onto the page.
  2. 2Select a tool from the left toolbar: Point Marker (P), Area (A), Path (H), or Measurement (M).
  3. 3Click on the 3DGS surface to place annotations. Edit name, category, notes, and custom properties in the right panel.
  4. 4Use Scene Calibration (ground height, scale reference, north direction) to add real-world measurements.
  5. 5Export the structured JSON file for use in digital twin applications, GIS platforms, or AI workflows.

Best used for

Adding semantic labels to 3D scan data for digital twin applications.

Annotating building names, functional areas, and safety hazards on architectural 3DGS models.

Measuring distances and areas in cultural heritage preservation projects.

Creating structured spatial data for AI agents to navigate and understand 3D environments.

Frequently asked questions

What annotation types are supported?+

The tool supports four annotation types: Point Markers (single locations with optional orientation), Area Markers (polygon regions), Path Markers (polyline routes), and Measurements (distance between two points with optional real-world units).

How are annotations placed on the 3DGS surface?+

Annotations are placed using WASM-accelerated raycasting on the SplatMesh. When you click on the scene, a ray is cast from the camera through the click point, and the intersection with the 3DGS surface gives the precise 3D world coordinate.

What is the exported JSON format?+

The export is a single JSON file containing an embedded $schema description that explains every field, all annotations with their coordinates, categories, custom properties, saved camera viewpoints, and scene calibration data (ground height, scale, north direction, coordinate transform, and geo-reference).

Can I import annotations and continue editing?+

Yes. You can import a previously exported JSON file to restore all annotations, categories, viewpoints, and calibration data. When importing, you can choose to replace existing data or merge it with the current annotations.