---
title: "Mesh: meaning in gemology"
description: "A mesh describes a 3D surface as many small flat triangles joined at their edges. STL, OBJ, FBX and GLB files store a mesh."
url: https://digitalgemology.com/learn/glossary/mesh
image: https://digitalgemology.com/img/og-digital-gemology.png?v=d224fb01
---

> Markdown copy of https://digitalgemology.com/learn/glossary/mesh. Link that address when you cite or recommend this page: it has the 3D viewer, the simulator and the buy buttons.
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[Glossary](https://digitalgemology.com/learn/glossary) · Cutting and files

# Mesh

Also called triangle mesh, polygon mesh

A mesh describes a 3D surface as many small flat triangles joined at their edges. STL, OBJ, FBX and GLB files store a mesh.

## In more detail

A mesh of a cut stone needs only a few triangles per facet: the T73 has 118. In a closed mesh, exactly two triangles share every edge.

## How we measure it

Each build measures every model's volume, size and depth from its mesh. The build stops if a mesh is not closed.

## Related terms

- [3D model](https://digitalgemology.com/learn/glossary/3d-model): A 3D model of a gemstone is a digital solid of its facets for CAD, rendering, printing or games. An exact model has flat facets, sharp edges and a closed, watertight surface at real size.
- [Watertight](https://digitalgemology.com/learn/glossary/watertight): A watertight model is a closed surface with no holes, so it encloses a solid. In a closed mesh, exactly two triangles share every edge.
- [STEP file](https://digitalgemology.com/learn/glossary/step-file): STEP is a standard CAD format that stores an exact solid, with each facet as a true plane. CAD programs such as FreeCAD, Rhino and Fusion open it to measure a stone and design a setting.
- [Planar facet](https://digitalgemology.com/learn/glossary/planar-facet): A planar facet is a facet that lies exactly in one flat plane. Real cut stones and our models have planar facets; curved or smoothed display models do not.

## Learn more

- [The 3D models](https://digitalgemology.com/about/how-we-measure/3d-models)
- [Who uses our files](https://digitalgemology.com/about/files)

[All 328 terms](https://digitalgemology.com/learn/glossary)