k3d/share/shaders/k3d_superplank.sl:109:  float shadlen;		/* length of a unit of shader space */
k3d/share/shaders/k3d_superplank.sl:280:      shadlen = overallscale / length(ntransform("shader", NN));
k3d/share/shaders/k3d_superplank.sl:283:      N = calculatenormal(P + (Km * shadlen * disp) * NN);
