cad

name: cad description: Computer-aided design principles and tools license: MIT compatibility: opencode metadata: audience: engineers, designers, manufacturers category: engineering

What I do

• Create 2D drawings and 3D models of mechanical parts
• Generate technical documentation and manufacturing files
• Perform geometric constraint solving and parametric modeling
• Support assembly design and component routing
• Export designs for manufacturing or simulation

When to use me

• When creating mechanical designs for manufacturing
• When generating detailed engineering drawings
• When building 3D models for visualization or simulation
• When designing assemblies with multiple components
• When preparing files for CNC machining or 3D printing

Key Concepts

CAD File Formats

Parametric Modeling

# Example: Creating a parameterized part
class ParametricPart:
    def __init__(self, **dimensions):
        self.dimensions = dimensions
    
    def create_sketch(self, points):
        """Create 2D profile from points"""
        return {
            "type": "sketch",
            "entities": points,
            "constraints": []
        }
    
    def extrude(self, sketch, depth):
        """Extrude sketch to create 3D feature"""
        return {
            "type": "extrude",
            "profile": sketch,
            "depth": depth,
            "direction": "positive"
        }
    
    def create_hole(self, location, diameter, depth):
        """Create a hole feature"""
        return {
            "type": "hole",
            "center": location,
            "diameter": diameter,
            "depth": depth
        }

Geometric Constraints

• Coincident: Two points occupy same location
• Collinear: Points lie on same line
• Parallel: Lines have same direction
• Perpendicular: Lines intersect at 90°
• Concentric: Centers coincide
• Equal: Dimensions or radii match
• Tangent: Curves touch without crossing

Assembly Design

# Assembly constraint types
ASSEMBLY_CONSTRAINTS = {
    "mate": {
        "description": "Two faces in contact, opposite directions",
        "degrees_removed": 3
    },
    "flush": {
        "description": "Two faces coplanar",
        "degrees_removed": 2
    },
    "angle": {
        "description": "Constrained angular relationship",
        "degrees_removed": 2
    },
    "insert": {
        "description": "Axial insertion (e.g., pin in hole)",
        "degrees_removed": 2
    }
}

Common CAD Software