class ShedDoorKnob : Model {
    
    val stemD = 24
    val axelD = 14
    val stemL = 12
    val holeZ = 8

    fun profile() : Shape2d {
        return PolygonBuilder().apply {
            moveTo(0,0)
            lineTo(15,0)
            lineTo(25,5)
            lineTo(25,20)
            lineTo(0,10)
        }.build()
    }

    override fun build() : Shape3d {
        val stem = (Circle( stemD/2 ) - Circle( axelD/2 ))
            .extrude( stemL ) -
        Cylinder( 30, 2 ).rotateY(90).translateZ(holeZ)
        
        val profile = Circle( 20 ).sides(6).roundAllCorners(3)
        val knob = ExtrusionBuilder().apply {

            crossSection( profile )

            forward( 5 ) // Chamfer front
            crossSection( 5 )

            forward( 13 ) // Main
            crossSection()

            forward(2) // Chamfer back
            crossSection(-2)

            crossSection( -5 ) // Merge with the stem
            forward(5)
            crossSection( Circle( stemD/2 ) )
            crossSection( Circle( axelD/2 ) )
            forward(-20)
            crossSection()

        }.build()

        return knob + stem.mirrorZ().bottomTo( knob.top ) 
    }
}