01 Export the right format
Send 3MF if your program offers it: it records the units, and keeps several parts together. STL is the most common and works well. OBJ is fine too. We can’t print from STEP, DWG or image files; export an STL first.
02 Get the units right
An STL file is just numbers, with no units. We read it as millimetres. If you designed in inches, either export in millimetres or tell us, and the quote tool has a switch for it. The tell-tale sign is a model 25.4 times too small.
03 Choose a sensible resolution
Curves in an STL are made of flat triangles. Too few and circles look like polygons; too many and the file is huge without looking any better. In most programs, an angular tolerance of 5–10° and a chord tolerance of 0.01–0.05 mm is right. A typical part is 1–20 MB.
04 Make it a closed solid
Every surface has to meet another with no gaps, like a balloon that holds air. Models made for games or animation often aren’t closed. Our model checker shows open edges; most CAD programs have a “repair” or “make solid” command.
05 One part or many?
If it’s a set of parts, a single 3MF with all of them is easiest. Separate STLs are fine too: send each one as its own request and mention the others in the notes, and we’ll put them together.
06 Don’t add supports or a raft
We add supports, brims and rafts ourselves when we slice, tuned to our printers. Send the part as you want it to come out.
Not sure your file is right? Open it in the model checker: it runs in your browser and shows holes, loose pieces and overhangs.