3D print preparation guide
3D Print File Preflight Checklist
Substantially updated 2026-10-24. First published 2026-09-09.
Print this page or download the blank record below. Mark one state per row: Pass means the stated property was checked against a known requirement; Review means a finding needs a decision; Unknown includes skipped, unsupported and failed checks. An unknown row never inherits another check's pass.
Download the editable preflight record (CSV).
File / revision: ____________________ Reviewer / date: ____________________
Source unit / expected size: ____________________ Printer / profile: ____________________
| Check and evidence to record | Mark one | Finding / next action |
|---|---|---|
| Input opens as the intended complete geometry; identify STL or supported 3MF package. | □ Pass□ Review□ Unknown | ____________________ |
| Units and a known reference span agree. For 3MF, verify declared units and placed items. | □ Pass□ Review□ Unknown | ____________________ |
| Every required item is present; separate intended shells from unwanted fragments. | □ Pass□ Review□ Unknown | ____________________ |
| Topology findings are understood: boundaries, over-shared edges, duplicates and winding. | □ Pass□ Review□ Unknown | ____________________ |
| Nominal dimensions fit the usable bed in the intended orientation, with brim/support space. | □ Pass□ Review□ Unknown | ____________________ |
| Critical walls and detail have a verification method; sampled values leave unsampled areas unknown. | □ Pass□ Review□ Unknown | ____________________ |
| The actual saved derivative reopens with intended bounds, surfaces and components. | □ Pass□ Review□ Unknown | ____________________ |
| Native slicer layers retain required features, cavities and supports under the intended profile. | □ Pass□ Review□ Unknown | ____________________ |
| Material, calibration, support removal and any functional/load requirement have a separate plan. | □ Pass□ Review□ Unknown | ____________________ |
Decision: proceed to the recorded next stage / clarify / return to source: ____________________
Unresolved checks and owner: ____________________ Recheck after revision: ____________________
Use the right evidence for each row
Run STL Print Preflight or 3MF Print Preflight for supported geometry screens. Record the actual method and settings. STL requires an assumed unit; a 3MF resource count is not the placed-item count. No printer profile means fit is unknown, not passed.
A collection report can retain completed, failed and cancelled files separately. Do not average a failed input into a clean collection score. A new revision needs a new check, even if its filename matches an earlier one.
Stop and choose a specific next action
Stop when intended scale, geometry or required parts cannot be established. Inspect an opening before filling it and identify a disconnected part before removing it. Preserve the original and recheck the saved result after a supported change. Use the STL finding interpretation guide for diagnostic branches, or the cross-format readiness guide for the reasoning behind each stage. This checklist records the decision; it does not duplicate that explanation or certify a physical print.
FAQ
What should I check before slicing an STL file?
Check the expected geometry, dimensions and unit assumption, printer fit, mesh warnings and relevant wall thickness, then verify any changed copy before slicing.
Does passing a mesh check mean a model will print successfully?
No. File checks do not determine supports, material behaviour, slicer settings, printer calibration or whether a design is suitable for its intended load.
Should I repair every STL warning before slicing?
No. Understand and locate the finding first. Preserve the original, change only what matters, and re-check the result.
Is 3MF better than STL for preflight?
3MF can declare units and represent placed build items, while STL is a simpler unitless mesh. Both still need geometry and slicer checks.