ASTHECA · PRACTICAL GUIDE
STL, PLY and GLB: what each format preserves
Geometry, color and materials serve different purposes when exporting a reconstruction.
STL: a surface
An STL describes a surface using triangles. The standard format does not preserve textures or materials and does not define a universal measurement unit. It is useful when the receiving tool primarily needs geometry. On import, confirm the scale against a known measurement and check the orientation. A file that opens successfully is not necessarily a file imported at the correct scale.
PLY: geometry with attributes
A PLY file can include attributes such as vertex colors alongside positions and faces. These can carry visual information with the surface, provided that the exporter writes them and the receiving application reads them. Different PLY readers may display different attributes. Test an exported file in the application where you actually intend to review it.
GLB: a portable scene
GLB is the binary form of glTF and can combine meshes, materials and other resources in a single file. It is convenient for sharing a scene with several structures and visual appearance. The format’s capabilities do not mean that every export contains all of them. Check what is included in the delivered file and how the receiving viewer presents it.
Appearance is not accuracy
A surface may look smooth because of lighting or normals without any change to its geometry. Similarly, colors derived from scan intensities are not a photograph of tissue. More shine or a more striking texture does not demonstrate higher accuracy. Keep the connection to the original scan slices and review the surface before using it in another workflow. Choose the export format according to the information you need to retain.