surfaceCurvature

SURFACECURVATURE Curvature on a surface from angle and principal curvatures.

   usage:
   KAPPA = surfaceCurvature(KAPPA1, KAPPA2, THETA)
   return the curvature KAPPA of surface with respect to direction THETA.

0001 function kappa = surfaceCurvature(kappa1, kappa2, theta)
0002 %SURFACECURVATURE Curvature on a surface from angle and principal curvatures.
0003 %
0004 %   usage:
0005 %   KAPPA = surfaceCurvature(KAPPA1, KAPPA2, THETA)
0006 %   return the curvature KAPPA of surface with respect to direction THETA.
0007 
0008 %   KAPPA1 and KAPPA2 are the principal curvatures of the surface at the
0009 %   considered point. THETA is angle of direction relative to angle of
0010 %   first principal curvature KAPPA1.
0011 %
0012 %   Examples:
0013 %   K = surfaceCurvature(KAPPA1, KAPPA2, 0) returns KAPPA1.
0014 %   K = surfaceCurvature(KAPPA1, KAPPA2, pi/2) returns KAPPA2.
0015 %
0016 %
0017 %   ---------
0018 %
0019 %   author : David Legland
0020 %   INRA - TPV URPOI - BIA IMASTE
0021 %   created the 07/04/2004.
0022 %
0023 
0024 %   HISTORY
0025 %   20/04/2004 change name and add doc.
0026 %   14/06/2004 correct creation date
0027 
0028 kappa = kappa1 * cos(theta).^2 + kappa2 * sin(theta).^2;