
sph2cart, orientation, lines and coordinates in 3d space / volume
Posted:
Feb 25, 2014 8:29 AM


Dear all, I've got a problem, which should be trivial, but I do not manage to solve this. Please help.
I'd like to get a circle around the coordinates of a line in 3D space. The planes of circles have to be oriented in the same direction as the line. I tried the following code below.
The result should show a line with two circles around each point, perpendicular to the line. However, the result is actually a line with two circles at the wrong positions.
What am I doing wrong?
Many thanx, Kees ===================
% Two coordinates that represents a line Crd(1,:) = [0,0,0]; Crd(2,:) = [1,1,1]; figure; plot3(Crd(:,1), Crd(:,2),Crd(:,3), '.');
% defining the orientation of the vector/line DCrd = diff(Crd); DCrd(end+1,:) = DCrd(end,:); [OrientCrd(:,1), OrientCrd(:,2), OrientCrd(:,3)] = cart2sph(DCrd(:,1), DCrd(:,2), DCrd(:,3));
% Setting up the plane around the two coordinates, which is perpendicular % to the direction of the line AziList = linspace(0, 2*pi, 36); EleList = pi/2; % swap of 90 degrees Radius = 4; clear TmpCrd ExtCrd; for n = 1:size(Crd,1) k = 1; for A = 1:length(AziList) for E = 1:length(EleList) [TmpCrd(k,1), TmpCrd(k,2), TmpCrd(k,3)] = ... sph2cart(OrientCrd(n,1)+AziList(A), OrientCrd(n,2)+EleList(E), Radius); k = k+1; end; end; ExtCrd(n,:,:) = TmpCrd + ones(size(TmpCrd,1),1)*Crd(n,:); clear TmpCrd; end; hold on; plot3(ExtCrd(:,:,1), ExtCrd(:,:,2),ExtCrd(:,:,3), '.'); hold off;

