3d Modelling

Target Domain

OpenSCAD script creation optimized for BOSL2 (Boston OpenSCAD Library v2).

This skill can be explicitly triggered by using the /scad command with a prompt, and applies to all files with the .scad extension.

Core Directives

• Library Inclusion: Always begin scripts by importing the standard BOSL2 environment via include <BOSL2/std.scad>. Never mix legacy BOSL v1 syntax with BOSL2.
• Parametric Design: Define all core dimensions, tolerances, and configuration parameters as variables at the top of the file.
• Leverage BOSL2 Primitives: Replace native OpenSCAD primitives with BOSL2 equivalents (cuboid, cyl, sphere) which natively support arguments like rounding, chamfer, or, and anchor.
• Attachment System: Use BOSL2's attachment and positioning functions (position(), orient(), edge_profile()) instead of manual translation/rotation arithmetic for complex sub-assembly alignments.
• Printability & Tolerances: Explicitly factor in 3D printing clearance variables (e.g., $fn = 64; for smooth cylinders, clearance = 0.2; for mating parts).
• Layer Height & Resolution: Use $fa and $fs to control facet angle and size for high-quality prints, adjusting based on the complexity of the geometry. Features like chamfers should not be smaller than the standard layer height of 0.2mm.
• Consistent Dimensions: Maintain consistent units (millimeters) and avoid mixing metric and imperial measurements. Use clear variable names to indicate the purpose of each dimension (e.g., wall_thickness, hole_diameter).
• Reduce Redundancy: Use the same variable for the same dimension across different modules to ensure consistency, and if necessary use multiples to reduce configuration complexity for similar dimensions, like ribbing_size = wall_thickness / 2.
• Design Principles: Additionally, consider the Design Principles for Reliably Printable 3D Models.

Code Structure

• Basic Template: The template.scad file provides a starting point for new designs, demonstrating the recommended structure and BOSL2 usage patterns.
• Module Organization: Group related geometric features into separate modules, and use descriptive names for clarity.
• Parameterization: All key dimensions and tolerances should be defined as top-level variables, allowing for easy adjustments without modifying the core logic.
• Preview Mode: Use the $preview variable to toggle between high-fidelity and low-fidelity rendering for faster iteration during development.
• Derived Calculations: Keep derived calculations below the /* [Hidden] */ marker to avoid cluttering the main parameter section.
• File Organization: Keep the file organized with clear sections for settings, modules, and main execution code.
• Examples: Include example usage snippets to demonstrate how to instantiate and combine modules effectively.
• Naming Conventions: Use clear and consistent naming for modules, variables, and files to improve readability and maintainability.
• Commenting: Include concise inline comments explaining non-obvious geometric transformations or design constraints. Comments should also be used to capture the rationale behind design decisions, especially when deviating from standard practices.

Quality Standards & Guardrails

• Modularization: Break complex designs down into distinct, reusable OpenSCAD modules.
• Performance: Structure CSG operations (difference, union, intersection) efficiently to minimize rendering overhead.
• Documentation: Include concise inline comments explaining non-obvious geometric transformations or design constraints.