             let q = d.length
             return BKPoint( x: -d.y/q, y: d.x/q )
         }
-        func normal3(_ t: BKFloat) -> BKPoint {
+        /*func normal3(_ t: BKFloat) -> BKPoint {
             let r1 = self.derivative(t).normalize()
             let r2 = self.derivative(t+0.01).normalize()
             // cross product

            n[1] = R10 * r1[0] + R11 * r1[1] + R12 * r1[2]
            n[2] = R20 * r1[0] + R21 * r1[1] + R22 * r1[2]
            return n
        }
        return self.threeD ? normal3(t) : normal2(t)
    }
    
    // MARK: -

extension BezierCurve {
    
    // MARK: -
    
    private var dpoints: [[BKPoint]] {
        var ret: [[BKPoint]] = []
