CAM Architecture & Job Management

Relevant source files

The following files were used as context for generating this wiki page:

• src/Mod/CAM/Roadmap/ADR/ADR-000.md
• [src/Mod/CAM/Roadmap/Functionality/Job Management.md](https://github.com/TryParashell/Parashell/blob/44ee26aec7068593a3b395d52c51e27d893d9283/src/Mod/CAM/Roadmap/Functionality/Job Management.md)
• src/Mod/CAM/Path/Main/Sanity/Sanity.py
• src/Mod/CAM/Roadmap/README.md
• [src/Mod/CAM/Roadmap/Functionality/Operation Configuration.md](https://github.com/TryParashell/Parashell/blob/44ee26aec7068593a3b395d52c51e27d893d9283/src/Mod/CAM/Roadmap/Functionality/Operation Configuration.md)
• [src/Mod/CAM/Roadmap/Functionality/Output Generation.md](https://github.com/TryParashell/Parashell/blob/44ee26aec7068593a3b395d52c51e27d893d9283/src/Mod/CAM/Roadmap/Functionality/Output Generation.md)

The CAM (Computer-Aided Manufacturing) system within Parashell is a robust framework designed to translate 3D modeling workflows into professional CNC machining instructions. It integrates modeling geometry, stock definitions, and toolpath generation into a cohesive "Job" structure, supporting both professional and hobbyist CNC workflows through parametric updates and extensibility via Python.

Sources: src/Mod/CAM/Roadmap/README.md:16-23, src/Mod/CAM/Roadmap/ADR/ADR-000.md:14-16

Core CAM Components

The architecture is centered around the Job object, which acts as the top-level container for all machining project data. It manages the relationships between geometry, tools, and the final output parameters.

System Architecture Overview

The following diagram illustrates the primary entities managed within a CAM Job and their relationships.

Principal Entities

Entity	Description
Job	The top-level document object owning a single machining project.
Model	The part being machined, referenced via a Resource Clone to prevent mutation of original geometry.
Stock	The raw material representation. Types include FromBase, CreateBox, CreateCylinder, or NoStock.
Setup Sheet	A container for Job-specific default values like rapid speeds and safe-height expressions.
Operation (Op)	A single machining step (e.g., Pocket, Profile, Drilling) that produces a toolpath.
Tool Controller (TC)	The runtime pairing of a Tool Bit with specific spindle speeds and feed rates.

Sources: src/Mod/CAM/Roadmap/ADR/ADR-000.md:18-100

Job Management Workflow

Job management involves configuring the environment where operations occur, including fixture selection and operation ordering.

Job Setup and Creation

The creation process groups operations into jobs or setups. It allows for multi-part workflows where multiple parts are supported in a single job. However, multi-setup workflows (processing the same part across different setups in one job) are currently not supported.
Sources: src/Mod/CAM/Roadmap/Functionality/Job Management.md:7-31

Fixture and Work Coordinate Systems (WCS)

Fixtures in this context represent WCS selections (G54–G59.9). A Job can output multiple fixtures, and the system can optimize across these fixtures to minimize tool changes.
Sources: src/Mod/CAM/Roadmap/Functionality/Job Management.md:32-35, src/Mod/CAM/Roadmap/ADR/ADR-000.md:54-58

Operation Logic and Toolpaths

Machining operations are the functional units that generate toolpaths. They are configured via Feature flags (e.g., FeatureTool, FeatureDepths) and properties.

Toolpath Generation Flow

Operations rely on low-level motion-pattern functions called Generators to build segments of a toolpath. The final toolpath is a sequence of motion commands (G0, G1, etc.) attached to the operation.

Sanity Checks (CAMSanity)

The system includes a validation utility, CAMSanity, which performs pre-flight checks before output generation. It flags issues such as missing tools, unset feeds, or missing model geometry.

Key validation methods in src/Mod/CAM/Path/Main/Sanity/Sanity.py:

• _toolData(): Checks for legacy tools, duplicate tool numbers, and zero feedrates/spindle speeds.
• _stockData(): Validates that stock material is specified.
• _validate_job_structure(): Ensures the job contains at least one operation and base geometry.

Sources: src/Mod/CAM/Path/Main/Sanity/Sanity.py:270-380, src/Mod/CAM/Path/Main/Sanity/Sanity.py:464-490

Output Pipeline

The output pipeline converts internal toolpaths into machine-specific G-code via a Post-Processor.

Post-Processing Logic

1. Machine Definition: The .fcm file describes the physical CNC (axes, units, limits).
2. Post-Processor Selection: A Python script (e.g., <machine>_post.py) converts paths to G-code.
3. Setup Page: An HTML report (Sanity Check report) is generated for the operator.

Sources: src/Mod/CAM/Roadmap/ADR/ADR-000.md:139-151, src/Mod/CAM/Roadmap/Functionality/Output Generation.md:21-25

Configuration Table

Parameter	Type	Description
Start Depth	Property	Z height where cutting begins.
Step Down	Property	Axial increment between successive depth passes.
Step Over	Property	Radial increment perpendicular to tool axis across the surface.
Safe Height	Property	Z height for rapid moves within an operation.
Clearance Height	Property	Z height for safe rapids over physical fixtures/clamping.

Sources: src/Mod/CAM/Roadmap/ADR/ADR-000.md:73-88

Summary

The CAM Architecture in Parashell provides a structured, hierarchical approach to machining projects through the Job object. By decoupling tool geometry (Tool Bit) from machining parameters (Tool Controller) and utilizing a robust validation system (CAMSanity), the project ensures accuracy and safety in professional CNC workflows. Parametric integration allows the system to respond to modeling changes, though current recompute efficiency remains a focus for future development.
Sources: src/Mod/CAM/Roadmap/README.md:16-23, src/Mod/CAM/Roadmap/ADR/ADR-000.md:154-164