PLY organizes data into typed elements and properties. A file may contain vertices and polygon faces, or just point samples with additional attributes. This flexibility makes it useful in scanning and geometry workflows, but a PLY extension alone does not establish a triangle surface.
- Geometry
- Mesh faces index vertex positions. Point-only data does not define a surface.
- Encoding
- ASCII and binary encodings exist. The local tools accept ASCII or binary little-endian PLY 1.0 only.
- Appearance
- The supported mesh subset can display vertex normals and uchar RGB colors.
- Units
- No physical scale is inferred from comments or coordinate values; bounds remain in unspecified units.
A point cloud needs reconstruction before STL
An STL needs triangle facets. Connecting neighboring scan samples is a modeling decision that can change holes, boundaries and shape; these tools do not perform it. If your PLY has no face list, first use a dedicated surface-reconstruction workflow.
PLY→STL removes vertex color information
Supported planar polygons are triangulated and their coordinates retained, but STL output does not store the preview’s RGB colors or custom attributes. In the reverse direction, STL→PLY produces a deterministic little-endian mesh with double positions and triangular face lists, without fabricating color or units.