New Things

  • dT/ds (derivative of the Unit Tangent with respect to S) = rate of change in direction as we move along the curve.
  • ||dT/ds|| = “curviness” of the curve, curvature
  • κ = Curvature = ∥∥dT/ds∥∥
  • ρ = 1/κ = Radius of curvature

Curvature

  • Here, we see that when looking at curvature, you can imagine a circle that is tangent to a space curve.
  • A sharper curve would indicate a smaller tangent circle
  • A straight part of the curve would indicate that there is zero curvature
  • The radius of curvature (ρ) is the radius of that tangent circle

Torsion

τ = Torsion = twistiness of the curve = rate of change of direction at B as we move along the curve = ||dB/ds|| GENERAL FORM

  • Derivation for Torsion