cylinderSurfaceArea

CYLINDERSURFACEAREA  Surface area of a cylinder.

   S = cylinderSurfaceArea(CYL)
   Computes the surface area of the cylinder defined by:
   CYL = [X1 Y1 Z1  X2 Y2 Z2  R], 
   where [X1 Y1 Z1] and [X2 Y2 Z2] are the coordinates of the cylinder
   extremities, and R is the cylinder radius.
   The surface area of the cylinder comprises the surface area of the two
   disk-shape end caps.

   Example
     cyl = [0 0 0  1 0 0  1];
     cylinderSurfaceArea(cyl)
     ans =
        12.5664
     % equals to 4*pi

   See also
     geom3d, ellipsoidSurfaceArea, intersectLineCylinder

0001 function S = cylinderSurfaceArea(cyl)
0002 %CYLINDERSURFACEAREA  Surface area of a cylinder.
0003 %
0004 %   S = cylinderSurfaceArea(CYL)
0005 %   Computes the surface area of the cylinder defined by:
0006 %   CYL = [X1 Y1 Z1  X2 Y2 Z2  R],
0007 %   where [X1 Y1 Z1] and [X2 Y2 Z2] are the coordinates of the cylinder
0008 %   extremities, and R is the cylinder radius.
0009 %   The surface area of the cylinder comprises the surface area of the two
0010 %   disk-shape end caps.
0011 %
0012 %   Example
0013 %     cyl = [0 0 0  1 0 0  1];
0014 %     cylinderSurfaceArea(cyl)
0015 %     ans =
0016 %        12.5664
0017 %     % equals to 4*pi
0018 %
0019 %   See also
0020 %     geom3d, ellipsoidSurfaceArea, intersectLineCylinder
0021  
0022 % ------
0023 % Author: David Legland
0024 % e-mail: david.legland@inra.fr
0025 % Created: 2017-11-02,    using Matlab 9.3.0.713579 (R2017b)
0026 % Copyright 2017 INRA - Cepia Software Platform.
0027 
0028 H = distancePoints3d(cyl(:, 1:3), cyl(:, 4:6));
0029 R = cyl(:,7);
0030 
0031 S1 = 2*pi*R .* H;
0032 S2 = 2 * (pi * R.^2);
0033 
0034 S = S1 + S2;