A fast, lightweight, open-source 3D model viewer for Android. Zero trackers, no ads, and no internet permissions required.

Key Features:
* Binary & ASCII STL: opens complex 3D meshes smoothly, including CAD exports with custom headers or truncated files.
* Wavefront OBJ: streams geometric vertices and faces, supporting triangles, quads, and convex n-gons.
* Smooth OpenGL ES 3.0 Rendering: 4x MSAA anti-aliasing with flat screen-space derivative normals for high fidelity and reduced memory usage.
* Visualization Modes: Solid shaded, Solid + Edges, and Wireframe views.
* Responsive Touch Controls: 1-finger orbit rotation, 2-finger pan, pinch-to-zoom, and double-tap to reset camera.
* Adaptive Ground Grid: dynamic build-plate grid that automatically adjusts spacing to match model dimensions.
* Physical Model Inspection: view triangle count, dimensions in mm, volume in cm³, surface area in cm², file size, and parse time.
* Seamless Integration: open models via the built-in document picker, "Open with" in any file manager, or system Share sheet.
* Material You Design: dynamic theming with dark and light mode support.