public override bool getGuidance(Vector3D pos, ref Vector3D guide, ref float weight, float height)
        {
            if (!base.getGuidance(pos, ref guide, ref weight, height))
            {
                return(false);
            }
            // size: 5x2x1, meaning 12.5 x 5 x 2.5
            // approximated by y = -(x+6.25)^2*0.008, see http://tinyurl.com/gnm5akr
            // for X flip, see below

            var localCoords = Vector3D.Transform(pos, this.cubeBlock.WorldMatrixNormalizedInv);

            localCoords.X = -localCoords.X;             // just mirror, todo redo the equation
            if (localCoords.Z < -1.25 || localCoords.Z > 1.25)
            {
                return(false);
            }
            localCoords.Y -= height;             // guide height above rail -- so we track the actual slope
            // closest point to a poly is not entirely trivial and I cba solving it manually, so resort to the laziest approach possible: BINARY SEARCH.
            double x       = 0.0;
            bool   success = MinSearch.find_smallest(ref x, xpar => distance(localCoords.X, localCoords.Y, xpar), localCoords.X, -6.25, 6.25, 10);

            // MyLog.Default.WriteLine(String.Format("success {0} finding x {1} which has guidefn {2} at {3}", success, x, guidefn(x), localCoords));
            if (!success)
            {
                return(false);
            }

            var localGuidepoint = new Vector3D(-x, guidefn(x) + height, 0);
            var worldGuidepoint = Vector3D.Transform(localGuidepoint, this.cubeBlock.WorldMatrix);

            guide  += worldGuidepoint;
            weight += 1;
            return(true);
        }
        public override bool getGuidance(Vector3D pos, ref Vector3D guide, ref float weight, float height)
        {
            if (!base.getGuidance(pos, ref guide, ref weight, height))
            {
                return(false);
            }
            // size: 5x1x1, meaning 12.5 x 2.5 x 2.5
            // approximated by y = (x+6.25)^2*0.008-2.5, see http://tinyurl.com/j9q6fc4
            // except with flipped x because whyy

            var localCoords = Vector3D.Transform(pos, this.cubeBlock.WorldMatrixNormalizedInv);

            localCoords.X = -localCoords.X;             // just mirror, todo redo the equation
            if (localCoords.Z < -1.25 || localCoords.Z > 1.25)
            {
                return(false);
            }
            // "rail coords"
            localCoords.Y -= height;             // see above
            double x       = 0.0;
            bool   success = MinSearch.find_smallest(ref x, xpar => distance(localCoords.X, localCoords.Y, xpar), localCoords.X, -6.25, 6.25, 10);

            if (!success)
            {
                return(false);
            }

            var localGuidepoint = new Vector3D(-x, railfn(x) + height, 0);
            var worldGuidepoint = Vector3D.Transform(localGuidepoint, this.cubeBlock.WorldMatrix);

            guide  += worldGuidepoint;
            weight += 1;
            return(true);
        }