STL — geometry only
An STL describes shape but not colour. For a single-colour sign it is perfect: one tidy file that every slicer understands. For multicolour it is not enough on its own, because there is nowhere to record which part is which colour.
3MF — colour built in
A 3MF stores each part with its own material, so your slicer opens the sign already split by colour. This is the best choice for multi-material printers such as those with an AMS: load your filaments, assign them, and print. 3dprint.name exports a coloured 3MF using the core spec so it opens cleanly.
Split-STL pack — for manual swaps
No AMS? Export the split-STL pack: a zip with one clean STL per colour, all sharing the same origin. Import them together, assign a colour to each, and either use a multi-tool setup or a filament-change-at-layer approach.
Whichever you choose, the parts always line up because they share a common origin — so colours never drift out of registration.
Quick rule of thumb
- One colour → STL.
- Multicolour on an AMS / multi-material printer → 3MF.
- Multicolour with manual filament changes → split-STL pack.