STL File Format
STL is a common manufacturing file format that represents a 3D model's outer surface as a triangle mesh.
Definition
STL stores the outer shell of a three-dimensional model as triangular facets. 3D printing software slices this mesh into layers and creates machine paths. The format does not carry color, material, parametric features, or reliable unit information; it represents surface geometry only.
Related Terms
- FDM: a filament-printing process that commonly slices STL files.
- SLA: a resin-printing process that may need a denser, clean mesh for fine detail.
- STEP: a CAD exchange format that preserves editable solid geometry.
- DFM: checks for mesh integrity, wall thickness, and manufacturing orientation.
Common Uses
STL is used to share final print geometry for FDM and SLA quotes. The file should be closed, manifold, correctly scaled, and free of flipped normals. Choose enough export resolution to keep curved surfaces smooth.
Watchouts
Very low resolution makes curves look faceted; excessive resolution creates heavy files without improving production quality. Because STL does not reliably store units, state mm or inch in the RFQ. If the Creator may need to modify geometry, include a STEP file alongside the STL.