🏛️ 3D scanning with a smartphone: photogrammetry and Gaussian Splatting
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Turn a facade, a room, an object or a piece of land into a 3D model with a plain Android phone: it's now possible, and a new technique, Gaussian Splatting, has been producing impressively photorealistic results since 2023-2024. Architects, surveyors, craftspeople, online sellers: here's how to get started.
1. The three technologies, simply
| Technique | How it works | Strengths | Limits |
|---|---|---|---|
| Photogrammetry | Dozens of photos from different angles → a textured 3D mesh | Works on any phone, exports to CAD | Struggles with plain, shiny or transparent surfaces |
| LiDAR / depth sensor | A sensor measures distances directly | Fast, good scale | Rare on Android; range of a few meters |
| Gaussian Splatting (3DGS) | The scene is made of millions of small colored "splats" | Photorealistic rendering (reflections, vegetation, fine details) | Not a real mesh: less suited to measuring and CAD |
2. Android apps to know
- Polycam: photogrammetry, export to many formats.
- KIRI Engine: photogrammetry and Gaussian Splatting, very popular with 3D creators.
- Scaniverse: splat capture processed right on the phone.
- RealityScan (Epic Games): real-time guided photogrammetry.
Free and paid features change often: compare them on a small object before starting a real project.
3. A good capture: the golden rules
- Diffuse light: an overcast sky is ideal. Avoid harsh sun and hard shadows.
- 60 to 80% overlap between consecutive photos: every point must appear in several images.
- Walk around the subject in circles, at 2 or 3 different heights, instead of turning on the spot.
- No blur: move slowly, or take photos rather than video.
- Avoid glass, mirrors, water and plain white walls. Stick a few markers (tape, printed targets) on surfaces that are too uniform.
- Add a scale: a scale bar or tape measure in the scene, or two points whose exact distance you know.
4. For architects and surveyors
- As-built surveys: facades, interiors, heritage elements to document before works.
- Site progress: one scan a week to compare progress.
- Volumes (stockpiles, earthworks): possible, but reliable results need ground control points (GCPs) measured with a precise instrument (RTK GNSS or total station) and dedicated photogrammetry software.
- ⚠️ A phone scan doesn't replace an official survey. Always check a few dimensions with a tape or laser, and state the estimated accuracy.
5. Export formats
| Format | Use |
|---|---|
| OBJ / FBX | Textured mesh for 3D and CAD |
| GLB / glTF | Web, augmented reality, lightweight sharing |
| PLY | Point clouds, and the usual format for Gaussian Splats |
| LAS / LAZ / E57 | Point clouds for surveying and BIM |
| USDZ | Augmented reality on Apple devices |
Tip: a .ply splat can be shared and viewed in a web browser with open-source viewers (for example PlayCanvas's SuperSplat), with no software to install.
6. Bonus for online sellers
A GLB 3D model of your product can be shown in augmented reality on the customer's own desk. For a craftsperson or a small shop, that's a real edge over the competition.
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