For space curves of constant curvature the evolute has the same constant curvature
Modify the curve
tube thickness, 1 ... 16:
Radius, 0.1 ... 6:
slope, 0.02 ... 2:
log(Scaling factor), 0 ... 7:
The helices have the formulas
curve(t) = Rad*[cos(frq*t), sin(frq*t), slope*frq*t].
We choose frq = 1/(Rad*sqrt(1 + slope^2)) to keep the arclength of the
helix constant under parameter changes. The normals of the helix are drawn
until they meet the evolute, another helix with the same curvature.