Skip to content

gcode-parser.md

Latest commit

 

History

History
91 lines (63 loc) · 3.26 KB

gcode-parser.md

File metadata and controls

91 lines (63 loc) · 3.26 KB

GCode Parser

The gcode package is a standalone Go library for parsing OrcaSlicer gcode files. It has zero external dependencies and can be imported independently of the rest of bambu-middleman.

Installation

go get github.com/szymon3/bambu-middleman/gcode

Usage

import "github.com/szymon3/bambu-middleman/gcode"

// Parse from an io.Reader
result, err := gcode.Parse(reader)
if err != nil {
    log.Fatal(err)
}

// Check parse completeness
if result.Status == gcode.ParseOK {
    // all sections present and valid
}

// Total filament consumed (startup + all layers)
total := result.TotalUsage()
fmt.Printf("%.2f g, %.2f mm\n", total.WeightG, total.LengthMM)

// Filament used up to layer N (1-indexed, inclusive)
partial, err := result.ComputedUsage(50)

// Per-layer callback during parsing
parser := gcode.New(gcode.WithLayerHook(func(layer int, usage gcode.FilamentUsage) {
    fmt.Printf("Layer %d: %.2f g\n", layer, usage.WeightG)
}))
result, err = parser.ParseFile("path/to/file.gcode")

What's extracted

Metadata

Slicer name and version, generation timestamp, total layer count, max Z height, filament diameter and density, estimated print times (model, first layer, total).

Configuration

Filament type (PLA, PETG, ABS, ...), colour, vendor, nozzle temperature (normal and initial layer).

Filament usage

  • Per-layer consumption -- computed from E-axis motion commands (G0/G1/G2/G3)
  • Startup usage -- purge line and nozzle priming before layer 1, tracked separately
  • Footer totals -- slicer-reported values from the file tail (length, volume, weight, cost)

Filament is converted from extrusion length to volume and weight using the diameter and density from the file header:

volume_mm3 = length_mm * pi * (diameter/2)^2
weight_g   = (volume_mm3 / 1000) * density

Parse status

Status Meaning
ParseOK Header, config, all declared layers, footer present. Diameter > 0, density > 0.
ParsePartial File parsed but some sections missing or incomplete (truncated file, missing density, etc.).

Supported formats

  • Single-filament OrcaSlicer gcode -- files must start with ; HEADER_BLOCK_START
  • 3MF archives -- the printer package can extract embedded gcode from OrcaSlicer .3mf files (see printer.ExtractFromThreeMF)

Limitations

  • Multi-filament files are rejected at parse time. Detection: any filament_* config key with ; in the value (indicating multiple filaments) triggers an error, unless the value starts with " (quoted gcode snippet).
  • Tool changes: T1--T9 (single-digit) are rejected as multi-filament indicators. T0 is allowed. Multi-digit Bambu preset codes (T255, T1000) are silently ignored.
  • OrcaSlicer only -- other slicers produce different gcode comment formats and are not currently supported. If you use a different slicer with a Bambu printer and would like to help add support, see Compatibility & help wanted.

Layer hook

The WithLayerHook option registers a callback that fires after each layer is fully parsed:

gcode.New(gcode.WithLayerHook(func(layer int, usage gcode.FilamentUsage) {
    // layer is 1-indexed
    // runs synchronously on the parser goroutine -- keep it fast
}))