Make cylinder around set of points which represent sequential line
[V,F] = make_cylinder(X,dN,dr)
X : set of points 3D coordinates [N x 3]
dN : number of points consist cylinder
= 6 means hexagonal cylinder will be made
dr : radius of cylinder (same unit with X)
2014-11-10 Masa-aki Sato
Copyright (C) 2011, ATR All Rights Reserved.
License : New BSD License(see VBMEG_LICENSE.txt)0001 function [V,F] = make_cylinder(X,dN,dr) 0002 % Make cylinder around set of points which represent sequential line 0003 % [V,F] = make_cylinder(X,dN,dr) 0004 % X : set of points 3D coordinates [N x 3] 0005 % dN : number of points consist cylinder 0006 % = 6 means hexagonal cylinder will be made 0007 % dr : radius of cylinder (same unit with X) 0008 % 0009 % 2014-11-10 Masa-aki Sato 0010 % 0011 % Copyright (C) 2011, ATR All Rights Reserved. 0012 % License : New BSD License(see VBMEG_LICENSE.txt) 0013 0014 % 各線分に沿って dN 角柱を作り、patchを生成する 0015 0016 [N, d] = size(X); 0017 if d ~= 3, error('data dimension error'); end 0018 0019 % dx : line segment direction [N x 3] 0020 dx = diff(X); 0021 dx = [dx; dx(end,:)]; 0022 0023 [dY,dZ] = make_orthogonal_vec_old(dx); 0024 0025 % incremental angle of cylindrical points 0026 ang = 2*pi/dN; 0027 da = ang*(0:dN-1); 0028 % [Y,Z] coordinate of cylindrical points 0029 y = cos(da); 0030 z = sin(da); 0031 0032 % make dN points for each N points 0033 V = zeros(dN*N,3); 0034 xyz = zeros(N,3,dN); 0035 0036 % make cylindrical points around X with radius dr 0037 for m=1:dN 0038 xyz(:,:,m) = X + dr*(dY*y(m) + dZ*z(m)); 0039 end 0040 0041 % find nearest point from xyz(n,:,1) to xyz(n+1,:,:) 0042 % which is cylindrical points in next X(n+1,:) 0043 % and reorder the next cylindrical points xyz(n+1,:,:) 0044 for n=1:N-1 0045 xn = xyz(n,:,1); % current 1st point 0046 xp = xyz(n+1,:,:);% next cylindrical points 0047 xp = reshape(xp,[3,dN]); 0048 0049 % distance from xyz(n,:,1) to xyz(n+1,:,:) 0050 dp = vb_repadd(xp, -xn(:)); 0051 dd = sum(dp.^2,1); 0052 % nearest point index 0053 [tmp, imin] = min(dd); 0054 0055 % reorder xyz(n+1,:,:) 0056 ind = imin + (0:dN-1); 0057 ind = mod(ind-1,dN) + 1; 0058 xyz(n+1,:,:) = xyz(n+1,:,ind); 0059 end 0060 0061 % cylindrical points of X(n,:) 0062 % : xyz(n,:,m) 0063 % = V( dN*(n-1) + m, :) 0064 nj = 0:dN:(dN*(N-1)); 0065 0066 for m=1:dN 0067 V(nj + m,:) = xyz(:,:,m); 0068 end 0069 0070 %--- Example of vertex & patch 0071 % 1 2 3 1 0072 % |/ |/ |/ | 0073 % 4 5 6 4 0074 %--- n=1, dN=3 0075 % F = [n n+1 n+dN; 0076 % n+1 n+dN n+1+dN] 0077 % There are 2*dN patches for pair of consecutive cylindrical points 0078 F = zeros(2*dN*(N-1),3); 0079 0080 % make patch index 0081 for i=1:N-1 0082 np = dN*(i-1); % start point index 0083 nf = 2*dN*(i-1);% start patch index 0084 0085 for n=1:dN 0086 if n==dN, 0087 m = 1; 0088 else 0089 m = n+1; 0090 end 0091 0092 % F = [n n+1 n+dN; 0093 % n+1 n+dN n+1+dN] 0094 F(nf+n,:) = [n m n+dN] + np; 0095 F(nf+dN+n,:) = [m m+dN n+dN] + np; 0096 end 0097 end