Technical context
STL commonly needs an externally agreed unit. 3MF can declare units and package additional data, though slicer-specific project settings are not universally portable. G-code targets a particular printer configuration and should be regenerated when the receiving machine differs.
Practical workflow
Retain editable CAD and a documented slicing project alongside exported files. Inspect unfamiliar projects before using their settings. Sharing geometry is generally different from asking someone to run pre-generated machine commands; preserve that distinction in your archive and production handoff.
Calculation and units
Dimensions = max ? min coordinates. Closed oriented mesh volume = sum(a · (b × c)/6). Closure and intersections affect validity; a numerical sum alone is insufficient.
Worked example
X from ?10 to 30 gives 40 coordinate units. If millimeters are intended, width is 40 mm; box volume is not object volume.
Validate the outcome
Confirm units and repair geometry. Use slicer consumption for hollow or infilled prints and never invent STL print time.
Preserve the right artifact for each task
Editable CAD preserves constraints and design intent. A model export transfers geometry, a slicing project preserves a manufacturing setup, and G-code is the resulting machine-specific job. Archiving only instructions makes resizing or material substitution harder. 3MF can carry units and properties through its specification and extensions, but application-specific slicer settings may not transfer completely. Inspect the imported result rather than assuming the extension makes the whole process portable.
Use an explicit production handoff
For geometry, include units, overall dimensions, revision and required orientation or mating features. For a project, include application version, printer and filament profiles and deliberate overrides. For G-code, state machine compatibility and provenance; regenerate when the recipient's setup differs. Comments reporting normal duration or mass cannot prove safe temperatures, movements or startup routines. Keep read-only metadata analysis distinct from executing instructions and preserve the model for re-slicing.
Units and metadata answer different questions
An STL coordinate span of 40 has no intrinsically declared millimeter meaning. A known reference dimension establishes intended scale. A 3MF unit attribute can remove that ambiguity in a conforming model, while G-code interprets commands under machine conventions and modal state. These differences explain why a geometry analyzer, project inspection and machine compatibility check are complementary rather than interchangeable tools.
File-role comparison
| File | Main role | Important limitation |
|---|---|---|
| STL | Triangle geometry | No declared unit |
| 3MF | Structured model container | Extensions and app settings may vary |
| G-code | Machine instructions | Printer-specific compatibility |
Maintain a reproducible file chain
Keep source CAD, the intended geometry export, the accepted slicing project and final machine job with matching revision identifiers. Record units and profile versions at each transition. This chain permits a new material or size to be re-sliced from geometry instead of attempting unsafe edits to a machine instruction stream. It also makes a repair traceable when a mesh tool changes the shape.
For a 3MF handoff, inspect required extensions and application-specific data in the receiving tool. For STL, verify a known dimension because the format lacks declared units. For G-code, inspect metadata only as recorded claims and confirm machine compatibility independently. Unsupported or compressed instruction variants need a dedicated decoder. A parser that can display duration is not a motion simulator or an approval to execute the file.
Can3MF make any slicer project fully portable?
The container and core model conventions improve structured transfer, including unit information, but extensions and application-specific settings still require receiver support. Inspect required extensions and import warnings, then verify geometry and manufacturing profiles. Another tool may understand the mesh without reproducing every process choice. Retain a documented source and avoid claiming the file extension alone guarantees identical printing results across unrelated applications or machines.
Can normal metadata prove G-code is safe to print?
No. A comment with plausible duration or grams can coexist with incompatible commands. Metadata analysis does not simulate motion, thermal waits or machine constraints and must not execute the file. Confirm printer, firmware, nozzle and material compatibility independently and regenerate from known geometry when practical. Keep the instruction stream's provenance explicit; read-only inspection is useful information, not a machine execution approval.