slicing

Slicing Pipeline

The orca.slicing module exposes SlicingPipelineCapabilityBase for plugins that run at points in the slicing pipeline or at the exported-G-code post-processing seam.

Base class	get_type() returns	Required methods	Invoked by
orca.slicing.SlicingPipelineCapabilityBase	SlicingPipeline	get_name(), execute(self, ctx) -> ExecutionResult	the slicing pipeline and G-code export path

Context

import orca

class Stamp(orca.slicing.SlicingPipelineCapabilityBase):
    def get_name(self):
        return "G-code Stamp"

    def execute(self, ctx):
        if ctx.step != orca.slicing.Step.psGCodePostProcess:
            return orca.ExecutionResult.success()
        with open(ctx.gcode_path, "a", encoding="utf-8") as gcode:
            gcode.write("\n; stamped by a plugin\n")
        return orca.ExecutionResult.success("G-code updated")

During geometry steps, ctx.print and (for object-scoped steps) ctx.object expose the live slicing graph. These references are valid only during execute(ctx). ctx.step identifies the current hook, and ctx.config_value(key) reads a resolved print setting.

At orca.slicing.Step.psGCodePostProcess, ctx.print and ctx.object are None. The context provides gcode_path, host, and output_name; the plugin edits the working G-code file in place. This step runs after classic post-processing scripts and may run separately for file export and network upload.

The capability runs on the slicing worker thread. Do not call orca.host.ui.* from it: the GUI may be waiting for slicing to finish, so marshaling a UI call can deadlock. Use the log or the execution result to report outcomes.

Pipeline steps

The exposed orca.slicing.Step enum includes geometry steps such as posSlice, posPerimeters, posPrepareInfill, posInfill, posIroning, posContouring, posSupportMaterial, and posSimplifyPath, plus generated-structure steps psWipeTower and psSkirtBrim. The psGCodePostProcess step is the export seam described above.

Important

Pipeline plugins can mutate the live slicing graph and affect generated output. Filesystem access is audited: writing to the G-code file at psGCodePostProcess needs no prompt, since its folder is a pre-approved allowed root for the duration of that call. Any other filesystem/network/process action prompts the user with a Yes/No dialog the first time, and the answer is remembered for that plugin. See Plugin Audit Hook.

See Registry for registration and Host for the model and geometry bindings.