On the normal we draw the segment equal to the radius of curvature at the point (Figure ). Figure 1. For each point of the curve (assuming ), we can find the center of curvature. The set of all centers of curvature of the curve is called the evolute of the curve.

How is evolute calculated?

The Evolution Index is basically the growth rate of a product relative to the growth rate of the market. For example, the EI for the product Calcigard should be (20.52/31.66)*100 = 64.81. The EI for the market is always 100 i.e. (31.66/31.66)*100.

What is the evolute of a parabola?

The evolute of a curve (blue parabola) is the locus of all its centers of curvature (red). The evolute of a curve (in this case, an ellipse) is the envelope of its normals.