File formats
Watertight mesh (manifold)
Also known as: manifold · malla cerrada · malla estanca · watertight · non-manifold · malla abierta
Short definition
A watertight or manifold mesh is one where every edge belongs to exactly two faces, so the solid has no holes and the slicer can tell what is inside from what is outside.
Full definition
It is the silent requirement of every print: to fill a part the slicer has to decide which volume is inside, and that is only possible if the surface is fully closed. A mesh with holes, inverted faces or edges shared by three faces is called 'non-manifold' and produces absurd results: walls that vanish, infill that spills out, hollow parts where there should be material. Modern slicers quietly repair the simple cases, but the complicated ones must be fixed in a mesh program before slicing.
Related terms
- STLSTL is a file format that describes a 3D object's surface as a mesh of triangles, with no colour, no units and no printing information.
- SlicerA slicer is the program that cuts a 3D model into horizontal layers and generates the G-code with the paths, temperatures and speeds the printer will execute.
- InfillInfill is the internal structure the slicer generates inside the part, expressed as a percentage of material relative to a solid block.
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