Update README.md

README.md

@@ -1,6 +1,33 @@
 ---
-title: Sparse2City3D
+title: Sparse Multi‑View 3D (Urban Planning)
+emoji: 🏙️
+colorFrom: gray
+colorTo: blue
 sdk: gradio
+sdk_version: 4.44.0
 app_file: app.py
 pinned: false
----
+---
+
+Upload **3–30** images of an outdoor scene and get back:
+- **fused point cloud** (`fused.ply`)
+- **textured‑agnostic mesh** (`mesh.obj`) and **`mesh.glb`** for GIS/CAD viewers
+
+### Capture Tips
+- Walk an arc with ~60–70% overlap between frames.
+- Mix wide + closer shots; include ground/verticals.
+- Avoid heavy motion (cars/people) if possible.
+
+### Controls
+- **Matching mode**: `sequential` (good if you walked along a path), `spatial`, or `exhaustive` (slower, more robust for sparse unordered sets).
+- **Poisson depth / target triangles**: increase for more detail; decimate for lighter meshes.
+
+### Outputs
+- Preview loads the **GLB**. Download the **OBJ** and **PLY** for further analysis.
+
+### GIS / Urban workflows
+- Mesh is in **arbitrary scale**. Align in QGIS/ArcGIS/Blender using known distances or control points to metric scale.
+- For true georeferencing, add GCPs / scale bars in the scene and fit in external tools.
+
+### Compute
+- Works on **CPU** (slower). If your Space has CUDA, SIFT and PatchMatch will use GPU where possible.