Source: src/settings/README.md — this page is rendered directly from the file in the repository. Edit it there.

Slicing Parameters & Settings

Configuration for slicing behavior and printer control. All values stored as JSON.

Quick Reference

Slicing Parameters (params.*)

Parameter	Type	Default	Range	Effect
layer_height	mm	0.2	0.1–0.4	Distance between layers
wall_thickness	mm	1.2	0.8–2.0	Perimeter width
infill_density	0–1	0.2	0.0–1.0	0=hollow, 1=solid
print_speed	mm/s	60	20–100	Nozzle movement speed
nozzle_temp	°C	210	180–250	Heat level (material-dependent)
bed_temp	°C	60	20–100	Bed heat (material-dependent)
seam_position	enum	nearest	see Seam Position	Where each closed-loop seam sits
min_infill_extrusion_mm	mm	0.4	0.0–nozzle	Drops sub-threshold solid-infill segments to cut tiny travels
coasting_distance_mm	mm	0.2	0.0–1.0	Length of un-extruded tail at the end of each path

Bridge & overhang (params.*)

Parameter	Type	Default	Effect
bridge_speed	mm/s	25	Print speed for bridge / overhang-perimeter extrusions
bridge_flow_ratio	0–1	0.8	Flow multiplier for bridge lines (less material = less sag)
bridge_anchor_mm	mm	0.4	Inflate the bridge region outward to anchor strands into solid material
bridge_min_area_mm2	mm²	0.5	Drop bridge candidates smaller than this; reclassified as BottomSurface
bridge_noise_filter_mm	mm	0.05	Morphological-open radius to wipe sub-pixel slivers before bridge detection
bridge_fan_speed	0–1	1.0	Cooling fan duty for layers that contain bridges

Global Settings (top-level)

Field	Type	Default	Description
gcode_flavor	string	"marlin"	Firmware dialect ("marlin" or "klipper")
start_print_gcode	string | null	null	Custom start G-code block or file path
end_print_gcode	string | null	null	Custom end G-code block or file path
lifecycle_markers	object	{}	Per-flavor layer lifecycle marker config (see below)

Config Priority

Settings are resolved in this order (highest priority first):

1. CLI arguments          (--layer-height, --gcode-flavor, --start-print-gcode, …)
2. slicer.json            (project config in CWD, or --config FILE)
3. ~/.config/slicer-engine/settings.json  (user config)
4. Built-in defaults

Each layer overrides only the keys it specifies; unset keys fall through to the next layer.

Project Config (slicer.json)

Place a slicer.json file in your project directory to set per-project defaults that override the user config without touching it. Only the keys you include are overridden.

{
  "params": {
    "layer_height": 0.15,
    "nozzle_temp": 215
  },
  "gcode_flavor": "klipper"
}

The file is auto-discovered when you run any slice command from the same directory. You can also point to it explicitly:

slicer-engine slice --input model.stl --config ./path/to/slicer.json

User Config (settings.json)

The persistent user-level config lives at:

Platform	Path
Linux	~/.config/slicer-engine/settings.json
macOS	~/Library/Application Support/slicer-engine/settings.json
Windows	%APPDATA%\slicer-engine\settings.json

Managed via the settings set / settings get subcommands (see below).

JSON Structure

Global settings file (settings.json or slicer.json)

{
  "params": {
    "layer_height": 0.2,
    "wall_thickness": 1.2,
    "infill_density": 0.2,
    "print_speed": 60.0,
    "nozzle_temp": 210.0,
    "bed_temp": 60.0
  },
  "gcode_flavor": "marlin",
  "lifecycle_markers": {
    "klipper": {
      "enabled": true,
      "layer_change": ";LAYER_CHANGE",
      "z_marker": ";Z:{z}",
      "height_marker": ";HEIGHT:{height}",
      "before_layer_change": ";BEFORE_LAYER_CHANGE",
      "after_layer_change": ";AFTER_LAYER_CHANGE",
      "type_annotation": ";TYPE:{type}",
      "width_annotation": ";WIDTH:{width}mm"
    }
  }
}

start_print_gcode and end_print_gcode are omitted from the file when null. lifecycle_markers is omitted entirely when the map is empty (i.e. all defaults are in effect).

Lifecycle Markers

Layer lifecycle markers are comments that slicer-aware firmware and post-processing scripts use to track progress, drive LED effects, pause at layers, etc.

How it works

Each firmware flavor can have its own LifecycleMarkerConfig entry in the lifecycle_markers map. Flavors not present in the map use the built-in defaults (enabled, standard OrcaSlicer/PrusaSlicer comment format).

When enabled: false, the generator emits a minimal ; layer z=… comment instead of the full lifecycle block.

Per-flavor configuration (LifecycleMarkerConfig)

Field	Default emitted comment	Supported placeholders
enabled	true	—
layer_change	;LAYER_CHANGE	{z}, {height}
z_marker	;Z:{z}	{z}
height_marker	;HEIGHT:{height}	{height}
before_layer_change	;BEFORE_LAYER_CHANGE	{z}
after_layer_change	;AFTER_LAYER_CHANGE	{z}
type_annotation	;TYPE:{type}	{type}
width_annotation	;WIDTH:{width}mm	{width}

All string fields are optional — omit them to keep the built-in default for that marker.

Placeholder reference

Placeholder	Replaced with	Example
{z}	Layer Z coordinate (3 d.p.)	0.200
{height}	Layer height from params (3 d.p.)	0.200
{type}	Extrusion role type name	WALL-OUTER, FILL
{width}	Extrusion role default width (2 d.p.)	0.40

Example: disable markers for Marlin, keep them for Klipper

{
  "lifecycle_markers": {
    "marlin": { "enabled": false },
    "klipper": { "enabled": true }
  }
}

Example: custom marker strings for a Bambu-style slicer

{
  "lifecycle_markers": {
    "marlin": {
      "enabled": true,
      "layer_change": ";BAMBULABS_LAYER_CHANGE",
      "z_marker": ";Z_HEIGHT:{z}"
    }
  }
}

CLI overrides

The --lifecycle-markers and --no-lifecycle-markers flags on the slice command override the enabled field from settings for the current invocation only:

# Force-enable markers regardless of settings
slicer-engine slice --input model.stl --lifecycle-markers

# Force-disable markers regardless of settings
slicer-engine slice --input model.stl --no-lifecycle-markers

Object settings (per-object override)

{
  "object_name": "detail_part",
  "overrides": {
    "layer_height": 0.1,
    "print_speed": 40.0
  }
}

When overrides is null, the object inherits all global settings.

CLI Commands

Get/Set Individual Values

Both flat aliases and full dot-separated paths are accepted:

# These are equivalent
slicer-engine settings get layer_height
slicer-engine settings get params.layer_height

# Set via flat alias
slicer-engine settings set layer_height 0.15

# Set via full path
slicer-engine settings set params.nozzle_temp 215

# Set top-level fields
slicer-engine settings set gcode_flavor klipper
slicer-engine settings set start_print_gcode "START_PRINT BED_TEMP=60 EXTRUDER_TEMP=210"
slicer-engine settings set end_print_gcode "END_PRINT"

# Clear an optional field
slicer-engine settings set start_print_gcode null

# JSON output
slicer-engine settings get layer_height --output-format json

Show All

slicer-engine settings show
slicer-engine settings show --output-format json

Validate

slicer-engine settings validate \
  --global global.json --object object.json

Checks constraints and ranges. Output: ✓ valid or error messages.

Diff

slicer-engine settings diff \
  --global global.json --object object.json

Shows which parameters are overridden:

layer_height    0.2 → 0.1    ✓ Override
print_speed     60  → 40     ✓ Override
nozzle_temp     210 → 210    (no change)

Validation Rules

Parameter	Constraint	Notes
layer_height	> 0	Typically ≤ nozzle diameter (0.4 mm)
wall_thickness	≥ 0.4 mm	At least one nozzle width
infill_density	0.0 ≤ x ≤ 1.0	Strict bounds
print_speed	> 0	Higher = faster but lower quality
nozzle_temp	180–250°C	Material-dependent (PLA≈210, PETG≈230)
bed_temp	20–120°C	Material-dependent (PLA≈60, PETG≈100)
gcode_flavor	"marlin" | "klipper"	Must be a known firmware dialect

Common Profiles

PLA

{
  "params": { "layer_height": 0.2, "nozzle_temp": 210, "bed_temp": 60 },
  "gcode_flavor": "marlin"
}

PETG

{
  "params": { "layer_height": 0.2, "nozzle_temp": 230, "bed_temp": 85 }
}

High-detail (Klipper)

{
  "params": { "layer_height": 0.1, "print_speed": 30, "wall_thickness": 1.6 },
  "gcode_flavor": "klipper",
  "start_print_gcode": "START_PRINT BED_TEMP=60 EXTRUDER_TEMP=210",
  "lifecycle_markers": {
    "klipper": { "enabled": true }
  }
}

Seam Position

params.seam_position controls where each closed perimeter loop begins and ends — the spot where the printer pauses, retracts, and lifts. That spot leaves a small visible blob ("the seam") on the outer wall.

Value	Vertex chosen per loop	Visual result	Best for
nearest (default)	Closest vertex to the previous path's end	Scattered seams; minimum travel & print time	Prototypes, infill-heavy parts
rear	Vertex with the largest Y	Single seam line at the back of the model	Display pieces (Benchy-style)
aligned	Vertex with the largest projection onto a fixed direction (+Y)	Consistent vertical seam line across all layers	Parts whose loops shift between layers
sharpest_corner	Vertex with the largest convex turn angle (falls back to nearest)	Seam hidden in geometry corners	Mechanical parts with hard edges
random	Hash of the loop's first-vertex bits (deterministic per loop)	Seam blobs spread evenly; no visible line	Cylinders, organic shapes

Override per-invocation from the CLI:

slicer-engine slice --input model.stl --seam-position rear

Set persistently in slicer.json / settings.json:

{ "params": { "seam_position": "sharpest_corner" } }

Hyphens and underscores are both accepted (sharpest-corner ≡ sharpest_corner). See core/README.md for the implementation details and the role-grouped path-ordering pass that consumes this setting.

Integration

See Also

• CLI Commands – Full command reference
• Slicing – How layer_height affects slicing
• Core pipeline – Path ordering & seam placement
• G-code generation – Smart-retract policy & travel sequence
• Root – Overview