Demo App Phase 2: Workplanes & Selectors

[gsdali]

Overview

Add CadQuery-style workplane operations and face/edge selectors.

Parent issue: #25
Depends on: #26

Goals

• Implement selector parser
• Add workplane stack
• Implement 2D sketch operations
• Add context-sensitive operations (hole at selected face)

Selector System

Face Selectors

Selector	Meaning	Implementation
">Z"	Top face (normal +Z)	Filter by normal.z > 0.9
"<Z"	Bottom face (normal -Z)	Filter by normal.z < -0.9
">X"	Right face	Filter by normal.x > 0.9
"<X"	Left face	Filter by normal.x < -0.9
">Y"	Front face	Filter by normal.y > 0.9
"<Y"	Back face	Filter by normal.y < -0.9

Edge Selectors

Selector	Meaning	Implementation
"|Z"	Edges parallel to Z	Filter by direction
"|X"	Edges parallel to X	Filter by direction
"#Z"	Edges perpendicular to Z	Filter by direction

API Additions

// Select faces and work on them
shape.faces(">Z")           // Select top face
     .workplane()           // Create workplane on face
     .hole(diameter)        // Drill hole

// Select edges for filleting
shape.edges("|Z")           // Select vertical edges
     .fillet(radius)

// 2D sketching
Workplane("XY")
    .rect(width, height)    // Draw rectangle
    .circle(radius)         // Draw circle
    .polygon(points)        // Draw polygon
    .extrude(height)        // Extrude to solid

Implementation

CadQuerySelectors.swift

struct Selector {
    enum Direction { case x, y, z }
    enum Comparison { case greater, less, parallel, perpendicular }
    
    static func parse(_ str: String) -> Selector? {
        // Parse ">Z", "<X", "|Z", "#Y" etc.
    }
    
    func filterFaces(_ faces: [Face]) -> [Face] {
        // Apply selector logic
    }
}

CadQueryWorkplane.swift

class CadQueryWorkplane: NSObject, CadQueryExports {
    var origin: SIMD3<Double>
    var normal: SIMD3<Double>
    var xDirection: SIMD3<Double>
    
    func rect(_ w: Double, _ h: Double) -> CadQueryWorkplane
    func circle(_ r: Double) -> CadQueryWorkplane
    func extrude(_ h: Double) -> CadQueryShape
}

Acceptance Criteria

• Face selectors work (">Z", "<Z", ">X", etc.)
• Edge selectors work ("|Z", "#Z", etc.)
• Workplane operations work
• 2D sketches can be extruded
• Holes can be placed on selected faces

Effort Estimate

~5 days