How to merge STL files
- Drop two or more files into the box above (you can add more later).
- Tick Lay parts out side by side to place them next to each other on the build plate, or untick it to keep their original coordinates (for assemblies).
- Download as STL, or as 3MF to keep the parts as separate objects.
STL or 3MF?
An STL stores everything as one mesh – the slicer sees a single object. A 3MF keeps every file as its own object, so you can still move, scale or colour them individually in PrusaSlicer, Bambu Studio or Cura.
Frequently asked questions
Are the files joined into one solid?
They are placed in one file but not fused (no Boolean union). Slicers print touching or overlapping parts correctly.
Is it free?
Yes – up to 3 downloads a day are free, with no sign-up or watermark. Pro (free for 7 days) makes it unlimited.
Is my file uploaded?
No. The file is processed in your browser and never leaves your device.