The writer declares millimetre units and the output is understood by Bambu Studio, PrusaSlicer, OrcaSlicer and other spec-compliant tools; it is roughly 70% smaller than STL on dense meshes. A few specialised tools expect a full build plate and may refuse a geometry-only 3MF - PrintBatch always writes the STL alongside.

No. The preflight reports open borders or double edges, which are very common in game and render assets. PrintBatch reports them instead of silently repairing (repairing would change your art). Many props slice fine as-is; for functional prints, close the shells in your modelling tool first.

The unit profile does not match your scene convention. Blender's default metric scene is 1 unit = 1 metre, while slicers read files as millimetres - the classic x1000 mix-up. Pick the right profile in the Units box, or press "Fix Unit Scale" when the red scale check appears. For print miniatures of real-world props, use "Custom multiplier": 100 turns a 0.96 m prop into a 96 mm model (1:10).

Never. All exports run on temporary copies; your scene, meshes and materials are untouched. It is safe to run on work-in-progress files.