Open preslice Docs

First layer height (first_layer_height)

First layer height is a number in mm. When printing with very low layer heights, you might still want to print a thicker bottom layer to improve adhesion and tolerance for non perfect build plates.

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_height process
Bambu Studio initial_layer_print_height process
OrcaSlicer initial_layer_print_height process
Cura layer_height_0 process
Creality Print initial_layer_print_height 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_height, initial_layer_print_height and layer_height_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 0.3 0 or more
Bambu Studio float mm 0.2 0 or more
OrcaSlicer float mm 0.2 0 or more
Cura float mm 0.3 not declared
Creality Print float mm 0.2 0 or more

Cura declares no range for this key, so nothing in the file bounds it.

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 height under its own name alongside the rest of the print settings. The file never leaves your machine, and nothing uploads.