What it stores
- B-Rep surfaces and solids
- Units and assembly structure
- Names, colours and sometimes PMI
3D FILE FORMAT
STEP: exact CAD, not a mesh
STEP is the exchange format of CAD: exact surfaces, units and assembly structure. Converters turn it into triangles for printing or the web, and that step is where precision is traded for a mesh.
At a glance
What it does not store
- Triangle meshes: they are generated on import
- Parametric history and features
- Rendering-friendly materials
When to use it
- Exchanging models between CAD systems
- Manufacturing and measurement
- A precise source before meshing
Limits to know
- Not a print format on its own
- Tessellation flattens curves
- Large assemblies are slow to parse
Convert to and from
STEP → STLConvert STEP to STLSTEP → OBJConvert STEP to OBJSTEP → GLBConvert STEP to GLBSTEP → 3MFConvert STEP to 3MF
Questions about the format
Is STEP better than STL?+
For CAD yes: STEP stores exact surfaces, units and assemblies. STL is a mesh for printing, produced by tessellating STEP.
Can STL keep exact dimensions?+
Overall size and placement are preserved, but curved surfaces become triangles; tolerances depend on tessellation.
Can I convert a STEP assembly?+
Yes, but heavy assemblies are slow in the browser. Convert the part you need, one at a time.