STEP · STL
STEP vs STL
STEP is a CAD source; STL is a print mesh. One keeps exact surfaces and units, the other keeps triangles a slicer can read. Converting STEP to STL is a one-way simplification.
| Criterion | STEP | STL |
|---|---|---|
| What it stores | B-Rep surfaces and solids | Triangles only |
| Precision | Exact curves and surfaces | Faceted approximation |
| Units | Declared in the file | None; slicers assume millimetres |
| Editing | Parametric CAD tools | Mesh editors only |
| 3D printing | Must be tessellated first | Slicers read it directly |
| File size | Depends on the model, often larger | Compact binary |
In short. Keep STEP as the source of truth and export STL for the slicer. Going back from STL to STEP is not possible: the exact surfaces and features are gone.
Convert between them
Format pages
Questions
Can I convert STL back to STEP?+
Not really. You can wrap a mesh in a STEP file, but the exact surfaces, features and constraints are lost.
Which is better for 3D printing?+
STL or 3MF: slicers read meshes directly. A STEP file must be tessellated first.
Does STEP keep the dimensions?+
Yes, exact dimensions and units; STL keeps the numbers but no unit and approximates curves.