File formats

Which files the app opens and which it writes, and what each format keeps: the parts tree, materials and vertex colours.

This page follows the format sheet inside the app. Open it there with Compare in the Export window.

Formats it opens

STEP (.step, .stp): The CAD exchange format. Converted by the local Python converter. Keeps the parts tree and materials. Open only: the app does not write STEP.
GLB: Binary glTF. Keeps the parts tree, full materials and vertex colours. The best all-round format.
glTF: The text form of GLB. The same capabilities, larger.
FBX: A common exchange format for Maya, Blender, Unreal and 3ds Max. Keeps the parts tree and materials.
OBJ: Universal, but with no transforms and no tree. Materials come from a separate .mtl file.
3MF: A 3D-printing format. Keeps the parts tree and materials. Open only.
STL: Geometry only, as a single mesh. Used for 3D printing.

STEP files go through the converter. The others load directly in the browser.

GLB: Parts tree, full materials, vertex colours. Optional Draco compression.
glTF: The same as GLB, as text.
FBX: Parts tree and materials. Binary FBX 7.4 by default, with a text (ASCII) version as a fallback.
USDZ: Parts tree and materials. For Apple Quick Look and Reality Composer. Write only.
OBJ: A flat list of parts, with the hierarchy folded into their names. Materials in a .mtl file.
STL: One mesh, geometry only.
PLY: One mesh, with a colour for every vertex. Write only.
CSV: A parts list. No geometry. Write only.

Hierarchy: Whether the format keeps the parts tree: groups, and groups inside groups.
Materials: Colour and shading for each part. “PBR” means the full set with metalness and roughness. A plain dot means colour only.
Vertex colours: A colour stored on every corner point of the mesh, with no separate material.