First-layer speed (first_layer_speed)
First-layer speed is a number in mm/s. Speed of initial layer except the solid infill part.
What does each slicer call it?
Five slicers, five spellings of one setting. The scope column is which preset the key belongs to, which is what decides whether changing it follows the printer, the filament, or the print profile.
| Slicer | Key | Scope |
|---|---|---|
| PrusaSlicer | first_layer_speed |
process |
| Bambu Studio | initial_layer_speed |
process |
| OrcaSlicer | initial_layer_speed |
process |
| Cura | speed_layer_0 |
process |
| Creality Print | initial_layer_speed |
process |
Where does it live in the file?
All five slicers file this under the process preset, so its value follows the print profile rather than the model. A .3mf is a zip, so unzip it and search for first_layer_speed, initial_layer_speed and speed_layer_0, or open the file in preslice and read the Raw tab, which searches every member at once.
Four of the five slicers write their settings into a sidecar part beside the geometry. Cura writes them into the model XML itself, so there is no config part to open.
| Slicer | Part | Format |
|---|---|---|
| PrusaSlicer | Metadata/Slic3r_PE.config |
INI, one key = value per line |
| Bambu Studio | Metadata/project_settings.config |
JSON, one flat object |
| OrcaSlicer | Metadata/project_settings.config |
JSON, one flat object |
| Cura | 3D/3dmodel.model |
XML metadata inside the model part, under a cura namespace |
| Creality Print | Metadata/project_settings.config |
JSON, one flat object |
What values are valid?
Each slicer declares its own type, default, and bounds for its key. They do not always agree, and where they disagree the file is still valid in both: the slicer that wrote it is the one that enforced its own rule.
| Slicer | Type | Unit | Default | Range |
|---|---|---|---|---|
| PrusaSlicer | float | mm/s or % | 45 |
0 or more |
| Bambu Studio | floats | mm/s | not declared | 0 or more |
| OrcaSlicer | float | mm/s | not declared | 1 or more |
| Cura | float | mm/s | 25 |
not declared |
| Creality Print | float | mm/s | 20 |
1 or more |
Cura declares no range for this key, so nothing in the file bounds it.
The slicers disagree on the type: PrusaSlicer, OrcaSlicer, Cura and Creality Print as float, Bambu Studio as floats. preslice reads all of them.
Every type, default, and bound above is read from the slicer's own field definitions rather than from measurement: PrusaSlicer's PrintConfig.cpp, Bambu Studio's PrintConfig.cpp, OrcaSlicer's PrintConfig.cpp, Cura's fdmprinter.def.json and Creality Print's PrintConfig.cpp.
Can I read it from my own file?
Yes, without installing a slicer. Open preslice and drop a .3mf on the page. It unzips and parses the file in your browser, and shows first-layer speed under its own name alongside the rest of the print settings. The file never leaves your machine, and nothing uploads.