If you've ever downloaded a model, printed it as-is, and it came out nothing like the photo, this is usually why. An STL is only a shape. It's a mesh of triangles. It doesn't know the layer height, speed, temperature, supports, orientation, infill, or wall count. Your slicer fills all of that in with whatever profile you happen to have loaded. A 3MF can be a whole project. It can carry the model already placed on the plate, oriented correctly, with the print profile, supports, and per-part colors that produced the photo. The catch: not every 3MF includes settings. Plenty are just an STL with a different file extension. So if you're buying a file, check whether the listing says the settings are included. When a plain STL is fine: simple shapes you enjoy dialing in your own settings When a 3MF with settings is worth it: multicolor prints with lots of parts print-in-place or moving parts, where tight clearances decide whether it works tiny detailed pieces How to open one: In Bambu Studio or Orca Slicer, go to File > Open Project, and choose to load the settings when it asks. Longer explanation: 3MF vs STL: what you're actually buying Do you usually use a file's settings as-is, or do you always use your own profile?   submitted by   /u/3dprintedmom   to   r/Women3dprinting [link]   [comments]