.3MF File Format – Geometry extensions

Extensions on this page

A Toolpath extension is also being drafted by the consortium; it is not published and not described here.

Beam Lattice

A b:beamlattice element inside a <mesh> adds beams (cylinders or cones) between the mesh’s vertices, for lattice structures. The mesh may then have no triangles.

Slice

Stores an object as a stack of 2D polygon layers, so a printer can use it without slicing. The mesh must still be present, but it may be a lower-resolution stand-in.

Each slice is the region between the previous slice’s top (or zbottom) and its own ztop. For objects of type model or solidsupport every polygon must be closed (its last segment ends at startv) and is filled by the core’s positive fill rule, applied in 2D. For support objects the polygons are open outlines that are never filled. Fewer than 2³¹ polygons per slice.

Displacement

Moves the surface of a mesh by a height map, for fine texture without millions of triangles. An object holds a d:displacementmesh in place of a mesh, with d:vertices/d:vertex (x, y, z) and d:triangles/d:triangle as in the core, all in the displacement namespace.

Texture values are normalised to 0–1 (divided by 2ⁿ−1). Within a triangle, the map coordinates, directions and factors are interpolated from the corners. Then d(u, v) = texture(u, v) × height + offset, or 0 outside the 0–1 range where the tile style is none, and each point moves to p + d × f × n. Colours and other properties are applied first, then the surface is displaced. Producers should use a plain mesh when no triangle is displaced.

Boolean Operations

An object may hold a bo:booleanshape as its shape: a base object changed by an ordered list of bo:boolean operands, each applied to the result so far.

In overlapping volume, material and volumetric properties come from the last overlapping object.