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.
In more detail
Only a watertight model has a volume, a weight and a clear inside for light. Many display models are not closed.
How we measure it
Each build stops if one of our meshes is not closed. A file of your own must enclose the same solid as its facets, to within 0.5% of its volume.
Related terms
- 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.
- 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.
- Convex: A convex stone has no inward corners: a straight line between any two points inside it stays inside. Most cut stones are convex; a heart, with its notch, is not.
- Measure your own stone: “Measure your own stone” lets three of our tools measure your own cutting file or 3D model. They use the same code and settings as for our cuts.