Export formats

Three buttons under the Timeline stats, present once a solid exists.

Button	Writes	File
STL	Binary STL	model.stl
OBJ	Wavefront OBJ	model.obj
STEP	AP214 solid model	model.step

All in millimetres, matching everything else.

Two of them are meshes and one is not, which is the whole of the choice: STL and OBJ carry triangles, STEP carries the faces and surfaces the triangles were drawn from. See export a solid.

What is in them

The finished solid, after every feature and every blend. STL and OBJ write it as a triangle mesh and carry the same geometry as each other.

STL is binary, with one normal per facet, taken from the triangle's own winding. The format has no way to say that a facet belongs to a curved surface.

OBJ carries vertices, normals, and faces, one-indexed in the usual way. Its normals are per vertex and follow the surface, so a bore opens in a viewer shaded as round as it looks here. It has no material file and no colour, so the per-part colours you see in the model view do not travel.

The triangle count next to the volume in the Timeline is exactly what the two mesh formats will write.

STEP writes every visible body as its own solid in one file, positioned where it stands here. The part carries a name: one body goes out under that body's name, several go out as Assembly.

Curves are approximated in a mesh, and not in STEP

A triangle mesh has only flat faces, so a hole leaves in STL or OBJ as a many-sided prism. For a printed part this is almost always finer than the process; for anything measured off the mesh, the surface is faceted by construction and reads that way.

Shading hides this and geometry does not. A curved face is lit from the surface it was built from, so it reads as smooth on screen and in OBJ, while the vertices sit exactly where the tessellation put them. Measure the mesh, not the picture.

STEP has no such limit. The bore goes out as the round surface it is, so measuring it downstream gives the hole rather than the polygon.

One thing to know about the surfaces it writes: a bore arrives as an exact rational B-spline rather than as STEP's own cylinder entity. The geometry is exact either way. A reader that recognizes holes by looking for cylinders will not fire on it.

What STEP does not carry

Edges derived by a boolean (the rim of a pocket, the line a blend meets a wall on) are written as fitted curves rather than as instructions to work the intersection out again. They sit within 0.01 mm of the true edge, which is a decade finer than anything the model view draws.

An imported mesh body has no real geometry behind it and cannot be written at all. The export says which bodies it left out.

What is absent

Format
IGES	Not available. STEP is the solid-model export
DXF, SVG	Not available. Sketch geometry cannot be exported on its own; only the solid
3MF, AMF	Not available
Colour, materials	Not written to any of the three

The only way to move an editable part between sessions or machines is Save and Open. See saved files.