R3.Geometry.Sphere.Intersection C# (CSharp) Method

        public Circle3D Intersection( Sphere s )
        {
            if( this.IsPlane || s.IsPlane )
                throw new System.NotImplementedException();

            double r = s.Radius;
            double R = this.Radius;

            Vector3D diff = this.Center - s.Center;
            double d = diff.Abs();
            if( Tolerance.Zero( d ) || d > r + R )
                return null;

            double x = ( d*d + r*r - R*R ) / ( 2*d );
            double y = Math.Sqrt( r*r - x*x );

            Circle3D result = new Circle3D();
            diff.Normalize();
            result.Normal = diff;
            result.Center = s.Center + diff * x;
            result.Radius = y;
            return result;
        }

        public static void GenImage()
        {
            int size = 1000;
            Bitmap image = new Bitmap( size, size );
            ImageSpace i = new ImageSpace( size, size );
            double b = 1.1;
            i.XMin = -b; i.XMax = b;
            i.YMin = -b; i.YMax = b;

            Vector3D cen = HoneycombPaper.CellCenBall;
            cen = H3Models.BallToUHS( cen );
            Sphere[] simplex = Simplex( ref cen );

            Sphere inSphere = InSphere( simplex );

            using( Graphics g = Graphics.FromImage( image ) )
            foreach( int[] reflections in AllCells() )
            {
                Sphere clone = inSphere.Clone();
                foreach( int r in reflections )
                    clone.Reflect( simplex[r] );

                Sphere ball = new Sphere();
                Circle3D inSphereIdealBall = ball.Intersection( clone );
                Circle3D inSphereIdealUHS = H3Models.BallToUHS( inSphereIdealBall );
                Circle inSphereIdeal = new Circle { Center = inSphereIdealUHS.Center, Radius = inSphereIdealUHS.Radius };

                using( Brush brush = new SolidBrush( Color.Blue ) )
                    DrawUtils.DrawFilledCircle( inSphereIdeal, g, i, brush );
            }

            image.Save( "threefifty.png", ImageFormat.Png );
        }