The short answer
STL is the universal mesh - bare triangles, no units or colour. 3MF is the modern mesh - geometry plus units, colour, multiple parts and print settings in one tidy file. STEP is a precise CAD format that must be converted before printing. OBJ is a mesh that can carry colour and texture, common from 3D-design and scanning tools. A printing service should accept all four. For most shops the practical rule is: take STL and 3MF as your primary upload formats (every slicer exports them), accept STEP for engineering customers and convert it to a mesh on intake, and allow OBJ for scanned or artistic models - then quote every file from its real geometry rather than asking the customer for dimensions.
| Format | Type | Stores | Best for |
|---|---|---|---|
| STL | Mesh | Geometry only | Universal exchange |
| 3MF | Mesh+ | Geometry, units, colour, parts, settings | Modern printing |
| STEP | CAD (solid) | Exact surfaces & solids | Engineering parts |
| OBJ | Mesh | Geometry, colour, texture | Design & scanning |
Compare two formats head to head
This page is the overview. If you are weighing up a specific pair, each comparison has its own guide with the detail this table flattens:
- 3MF vs STL - units, colour, separate parts, file size, and why an STL's missing units cause re-quotes.
- STEP vs STL - exact solids versus triangles, tessellation, and whether STP is the same thing.
- CAD vs STL - what the export step throws away, and which tolerance settings to use.
STL - the universal standard
STL ("stereolithography") describes a model as a mesh of triangles and nothing else. No units, no colour, no scale metadata. That simplicity is exactly why it became universal - every modeller and slicer reads and writes it.
The downsides matter for a service: because STL stores no units, a model can arrive ambiguously scaled, and because it's just a triangle soup, meshes can be non-watertight or have errors. It's still the safest lowest-common-denominator to accept.
3MF - the modern replacement
3MF ("3D Manufacturing Format") was built to fix STL's gaps. In one compact, compressed file it carries the mesh plus real-world units, colours, multiple objects, and even slicer settings. Project files from Bambu Studio and MakerWorld are 3MF under the hood, which is why a single file can hold a whole multi-plate, multi-part print.
If a customer can export 3MF, prefer it: you get the designer's intended scale, colours and part layout instead of guessing.
STEP / STP - precise CAD
STEP is a CAD interchange format that stores exact mathematical surfaces and solids, not triangles. That makes it the format of choice for engineering and functional parts, where precise dimensions matter.
You can't print a STEP file directly - a slicer needs a mesh - so it must be converted to STL first. The upside is that, because STEP holds the true geometry, that conversion can be done at whatever resolution the part requires.
OBJ - meshes with colour
OBJ is a mesh format like STL but it can also carry colour and texture (via a companion material file). It's common out of 3D-design suites, sculpting tools and 3D scanners. For single-colour FDM printing the extra colour data is often ignored, but accepting OBJ means customers coming from those tools don't have to convert anything first.
Which should you accept?
Ask for only one format and you turn customers away at the door. Accept STL and 3MF for ready-to-print meshes, STEP for CAD and engineering parts, and OBJ for design and scanning exports, and you'll handle almost everything anyone sends - without a back-and-forth asking them to re-export.
Accept all four, quote instantly
Filaquote reads STL, 3MF, STEP/STP and OBJ. STL and 3MF are analysed instantly in the customer's browser; STEP files are converted on our servers; and 3MF / Bambu Studio / MakerWorld projects keep their multi-plate and per-part detail. Every upload gets a live 3D preview and an instant, accurate price.
Add to Shopify→FAQ
What is the best file format for 3D printing?
3MF is the most capable for printing - it stores mesh, colour, units, multiple objects and settings in one file. STL is still the most common thanks to universal support. For a service, accepting STL, 3MF, STEP and OBJ covers almost everything.
Do I need to accept all four formats?
Accepting STL and 3MF covers the large majority of hobby and consumer work. Adding STEP is what opens the door to engineering customers, who tend to order repeatedly and at higher values, so it is usually worth it.
What about GLB, FBX and OBJ files?
OBJ is worth accepting: it is a plain mesh and comes out of sculpting and scanning tools. GLB and FBX are built for real-time graphics and animation rather than manufacturing, so it is reasonable to ask for an STL, 3MF or OBJ export instead.