A model opens at the wrong size
The model is a speck on the plate, or PrusaSlicer asks whether
The dimensions of the object from file %s seem to be defined in inches.
(Plater.cpp).
An STL stores bare numbers with no unit, so every slicer reads them as
millimetres. A part drawn in inches comes in 25.4 times too small, and one
drawn in metres 1000 times too small.
Can I print it anyway?
Only after you scale it. A part at a 25th of its size prints as a blob, if at all.
What does each slicer ask?
| Slicer | What it does with a tiny model |
|---|---|
| PrusaSlicer | Asks under The object is too small, for inches (line 1508) or meters (line 1490), and has File, Import, Import STL (Imperial Units) |
| OrcaSlicer | The object from file %s is too small, and maybe in meters or inches. under Object too small (Plater.cpp) |
| Creality Print | The same prompt as OrcaSlicer (Plater.cpp) |
| Bambu Studio | Nothing. The inch prompt is commented out (Plater.cpp) |
| Cura | Auto scaled model to {0}% of original size (ReadMeshJob.py), in steps of ten, so metres are fixed and inches are not |
Cura scales only with Scale extremely small models on in its preferences.
What about Object too large?
Bambu Studio asks
Your object appears to be too large, Do you want to scale it down to fit the heat bed automatically?
(Plater.cpp)
when a model is over ten times the bed. OrcaSlicer asks the same about the
print bed. Saying yes shrinks it to fit the bed, not to its real size, so
check the size first.
Is my file broken?
No. The numbers are right; the unit is missing. A .3mf declares its unit,
which is why the problem is rare there.
How do I check the real size with preslice?
- Drop the
.stlor.3mfon preslice.co. - Open the 3D View tab, or 3MF Content for a
.3mf. - Read the Size row under each mesh: width, depth and height.
If a bracket you drew 100 mm wide reads 3.94, it was drawn in inches. If it
reads 0.1, it was drawn in metres. A .3mf row names its declared unit,
such as in.
How do I fix the scale?
In the slicer, scale the part by 2540 % for inches or 100000 % for metres. In PrusaSlicer, answer yes to the prompt. preslice shows the size and does not change it.
Can I fix it at the source?
Yes. Export again from the CAD tool with millimetres set as the unit, or as a
.3mf, which carries its unit. See 3MF against STL.