The two-minute job most people open a desktop slicer for: make the model exactly the size you need — millimeters or percent — and export it ready to print.
Updated November 7, 2026 · Published by Forma3D
Open your STL (or 3MF/OBJ) in Forma3D from Files. In Object mode, tap the model so it's selected — the Transform panel controls everything about size, rotation and position.
In Transform, type the size you want. Two ways to think about it: millimeters — when the part has to fit something physical (pegboard slot, shelf, enclosure); or percentage — when you just want it bigger or smaller. Uniform scale is on by default so proportions stay intact.
Unlock the axes to stretch one dimension independently — useful for fixing a model that's subtly off, or intentionally distorting (a taller vase, a flatter logo). Be careful: non-uniform scaling skews holes, threads and anything meant to mate with real hardware.
After resizing (and any rotation), press Bake — it writes the current scale and rotation into the mesh vertices. This matters: some slicers read unbaked transforms inconsistently, and booleans/splits later behave better on baked geometry. Then export STL or 3MF back to Files — done.
Next step: send it to the printer, or split it if it's still bigger than your bed.
Open the STL in Forma3D, select the object, open Transform, and type the target size — in millimeters or as a percentage. Uniform scale keeps proportions; unlock axes to stretch one dimension. Export when done.
Millimeters when the part must fit something real (a shelf slot, a screw hole, your build plate). Percent when you just want it bigger or smaller — e.g., 120% to enlarge. Fit-to-plate workflows usually need mm.
Per-axis scaling stretched it — keep uniform scale unless you intentionally want the distortion. If a downloaded model imports at the wrong size entirely, check units: some files are authored in inches or in a different scale and need a one-time correction factor.
Scaling down only goes so far. For oversized models, split them instead — Forma3D's Separate tools cut a model into parts with alignment joints that reassemble after printing.
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