A file that opens successfully has passed one useful check: your software can read it. That leaves several separate questions. Is it the right revision? Did it arrive at the intended size? Does the project match your printer? Has anyone qualified the resulting part for its stated job?
For a workshop jig, keep those questions separate. A neat slicer preview is evidence of a proposed print, not evidence of fit or working performance. This guide is a file-review workflow, based on format specifications and slicer documentation. It is not a claim that we have printed or tested a particular jig.
First identify what you downloaded
STL describes a triangulated surface without defined physical units or slicer settings. A 3MF package can contain more information, including scene units and multiple objects. Slicer-specific settings may travel with it, but compatibility is not assured between programs. Prusa’s explanation describes both the advantages and that limitation.
| File you have | What to establish before proceeding |
|---|---|
| STL geometry | Intended dimensions, part identity and your own slicing setup |
| Generic 3MF geometry | Intended dimensions, included objects and whether settings are actually supplied |
| Slicer project saved as 3MF | Which printer, material and process settings were stored and which your slicer applied |
| Already sliced output | The exact machine and process it was produced for; request the source project if you need to revise it |
These are useful categories, not guarantees encoded in a filename. OrcaSlicer distinguishes generic 3MF exports from saved projects and supports sliced G-code or Gcode.3MF exports. A file ending in 3MF therefore needs inspection rather than an assumption that it contains only editable geometry. See the OrcaSlicer import/export documentation.
Check one known dimension before changing anything
Choose a dimension stated in the drawing or release notes: overall length, a clearly identified hole spacing or another unambiguous feature. Compare that value with the imported model. If they disagree, stop and resolve the source units or revision before rescaling.
The 3MF core specification defines model units, including millimetres and inches. That is useful information, but it does not establish that the author used the intended dimensions.
Do not resize a complete assembly merely to make one peg fit. That also changes its other features. Record the mismatch and ask for the intended revision or a documented adjustment. A fit check is more useful when it names the feature that failed.
Treat a project’s settings as information to review
In OrcaSlicer’s normal interface, inspect the active printer, nozzle, filament and process after opening a project. Compare them with the machine and material you will actually use. Review object count, orientation and any supplied modifiers before slicing. Imported presets may be applied, ignored or replaced with defaults depending on compatibility, as the Orca documentation explains.
Keep the original download and save your adaptation separately. A short name containing the source revision and your own setup makes it easier to distinguish the supplied file from your changes later.
Support for a format is also application-specific. Prusa’s supported-format list lists STL and 3MF and identifies 3MF as its project format. It does not promise that another slicer will reproduce every saved setting.
Make the print decision traceable
Before committing a plate, leave yourself a small record:
- Source page, author and revision, with the original filename.
- Expected part list and quantities, checked against the imported objects.
- One named dimension, its stated value and the value shown after import.
- Active printer, nozzle, material and process, with intentional changes recorded.
- Sliced preview checked for missing objects and unexpected results.
- Separate evidence still needed for physical fit and the intended workshop use.
If the package omits mating dimensions, hardware information or revision notes needed to understand it, ask the author before treating it as a finished jig. There is no benefit in efficiently printing the wrong revision.
Our design bench uses explicit project status for that reason. A design study can explain an idea without being a fabrication release. When a part is finally printed, its physical observations should remain tied to the exact revision and setup used. Changing the file format cannot supply that evidence.
Sources & further reading
Source information was checked for this guide’s publication date. Follow the manufacturer’s current manual for your exact tool.