Guide 5 min read

How to Open Your ButterySpace Bookmark ZIP

What's in the download, how to unzip it on Windows or Mac, which file to open in which slicer, why there are two files, and how to tell at a glance that it loaded correctly. Plus the three things that trip people up.

A ButterySpace guide, based on how the tool behaves in real maker workflows.

When ButterySpace finishes generating your bookmark, you download a ZIP file. This walks through exactly what is inside, how to unzip it on either operating system, which file to reach for in your slicer, and how to confirm at a glance that it loaded the way it should. We make these for our own projects, so the small snags below are the ones we actually hit.

Unzip it first

A ZIP is a sealed box. Most slicers will not load a file while it is still inside the box, and this is the single most common reason a brand-new maker gets stuck on "it will not open." Extract the contents first.

  • Windows: right-click the downloaded ZIP, choose Extract All, and pick a folder. Do not double-click the ZIP and drag a file out of the preview window. That preview is read-only and slicers often cannot reach it.
  • Mac: double-click the ZIP. macOS extracts it into a folder next to the original automatically. Open that folder, not the ZIP.

After extracting you will have a normal folder with two files in it. Those are what you open.

What's inside the ZIP

The ZIP contains exactly two files: the same bookmark geometry in two formats.

  • bookmark.3mf: the model in 3MF project format, readable by Bambu Studio, OrcaSlicer, PrusaSlicer, and Cura.
  • bookmark.stl: the same geometry as a single combined body, for the broadest slicer compatibility.

Both files describe a single combined object in shared millimetre coordinates, so there is nothing to align and no assembly step. There is no SVG in the ZIP; the bundle is built for 3D slicers, not cutters.

Why two files for the same bookmark?

It is a belt-and-suspenders thing. The 3MF is the modern format and carries the model in real-world millimetres with no ambiguity, which is why we list it first. The STL is the universal fallback that every slicer made in the last decade can open. If your slicer is new enough, open the 3MF. If you are on something older or unusual, the STL will always work. We ship both so you never have to come back and re-export. If you want the full comparison, the STL vs 3MF guide covers it.

Which file to open, by slicer

  • Bambu Studio: open bookmark.3mf (the STL also works). It loads as a single object, ready to slice.
  • OrcaSlicer / PrusaSlicer / Cura / other: open bookmark.stl. It is one combined body, so there is no import-as-assembly step. The 3MF opens in these too, but the STL is the simplest path.

However you import it, the model arrives as plain geometry. Choose your printer, filament, and layer settings as usual, then slice.

Did it load correctly? A quick check

Drop the file in and you should see a flat, bookmark-shaped slab, roughly 140 mm tall, lying on the plate with your artwork raised on the top face. If that is what you see, you are good. If something looks off, it is almost always one of these three:

  • It loaded tiny or enormous. That is a units mismatch, and it is why we hand you the 3MF. If you opened the STL and it came in at the wrong scale, switch to the bookmark.3mf, which states its millimetres explicitly, or set your STL import units to millimetres.
  • It looks like a plain flat slab with no design. You are probably looking at the underside. Rotate the view, or flip the part, and the raised artwork is on the other face.
  • It will not open at all. The file is still inside the ZIP. Go back and extract it (see the top of this guide).

Color is yours to choose. The files are geometry only. ButterySpace does not assign, bake in, or auto-load any colors, so a fresh import prints in one color. For a two-color or multi-color bookmark, paint it yourself in the slicer with the Color Painting brush or a filament change by height. It takes a minute, and the Bambu Studio color guide walks through both methods.

Before you hit print

A bookmark is a thin, flat part, which makes bed adhesion and layer height matter more than usual. None of that is baked into the file, so it is yours to set. The bookmark print settings guide has a sensible starting point: print flat, add a brim, and drop the layer height if your design has fine detail.