mesh_grow

 mesh_grow - explode vertices of mesh by specific distance

 FV = mesh_grow(FV,origin,dist)

 FV is a struct with fields:

 FV.vertices   - Nx3 matrix of Cartesian vertex coordindates (X,Y,Z)
 FV.faces      - Mx3 matrix of triangulation of FV.vertices

 origin        - 1x3 row vector, usually (0,0,0)

 dist          - how far to explode the mesh away from the origin;
                 this distance is relative to current distance from
                 the origin, not the total distance from the origin.

0001 function [FV] = mesh_grow(FV,origin,dist),
0002 
0003 % mesh_grow - explode vertices of mesh by specific distance
0004 %
0005 % FV = mesh_grow(FV,origin,dist)
0006 %
0007 % FV is a struct with fields:
0008 %
0009 % FV.vertices   - Nx3 matrix of Cartesian vertex coordindates (X,Y,Z)
0010 % FV.faces      - Mx3 matrix of triangulation of FV.vertices
0011 %
0012 % origin        - 1x3 row vector, usually (0,0,0)
0013 %
0014 % dist          - how far to explode the mesh away from the origin;
0015 %                 this distance is relative to current distance from
0016 %                 the origin, not the total distance from the origin.
0017 %
0018 
0019 % $Revision: 1.1 $ $Date: 2004/11/12 01:32:35 $
0020 
0021 % Licence:  GNU GPL, no implied or express warranties
0022 % History:  10/2002, Darren.Weber_at_radiology.ucsf.edu
0023 %
0024 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0025 
0026 
0027     xo = origin(1); yo = origin(2); zo = origin(3);
0028     
0029     Nvert = size(FV.vertices,1);
0030     
0031     fprintf('...mesh explosion...'); tic;
0032     
0033     for v = 1:Nvert,
0034         
0035         x = FV.vertices(v,1);
0036         y = FV.vertices(v,2);
0037         z = FV.vertices(v,3);
0038         
0039         % Find direction cosines for line from centre to vertex
0040         d = sqrt( (x-xo)^2 + (y-yo)^2 + (z-zo)^2 );
0041         
0042         l = (x-xo)/d; % cos alpha
0043         m = (y-yo)/d; % cos beta
0044         n = (z-zo)/d; % cos gamma
0045         
0046         % now decrease d by dist
0047         d = d + dist;
0048         
0049         % locate vertex at this new distance
0050         x = (l * d) + xo;
0051         y = (m * d) + yo;
0052         z = (n * d) + zo;
0053         
0054         FV.vertices(v,:) = [ x y z ];
0055     end
0056     
0057     t = toc; fprintf('...done (%5.2f sec)\n',t);
0058     
0059 return
0060