# How to move the axes so that they start from the center of the sphere (0,0,0)

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Atom on 11 Jun 2022
Commented: Atom on 12 Jun 2022
()1 How to move the axes so that they start from the center of the sphere (0,0,0)
(2) If I only want to keep the boundary curve and remove the interiors, what to do?
R = 1 ;
theta = linspace(0,2*pi) ;
phi = linspace(0,pi) ;
[T,P] = meshgrid(theta,phi) ;
X1 = R*cos(T).*sin(P) ;
Y1 = R*sin(T).*sin(P) ;
Z1 = R*cos(P) ;
zlim([0,5])
surf(X1,Y1,Z1,'EdgeColor','r', 'FaceColor', 'none', 'FaceAlpha', .5) ;
Image Analyst on 12 Jun 2022
I guess he wants just the convex hull points, like from convhulln
Atom on 12 Jun 2022
The interior is like as the post of Image Analyst (convhulln)

Star Strider on 11 Jun 2022
Try something like this —
R = 1 ;
theta = linspace(0,2*pi) ;
phi = linspace(0,pi) ;
[T,P] = meshgrid(theta,phi) ;
X1 = R*cos(T).*sin(P) ;
Y1 = R*sin(T).*sin(P) ;
Z1 = R*cos(P) ;
zlim([0,5])
surf(X1,Y1,Z1,'EdgeColor','r', 'FaceColor', 'none', 'FaceAlpha', .5, 'EdgeAlpha',0.5) ;
hold on
plot3([0 0],[0 0],zlim, '-k', 'LineWidth',1.5)
xline(0, '-k', 'LineWidth',1.5)
yline(0, '-k', 'LineWidth',1.5)
Ax = gca;
xt = Ax.XTick;
yt = Ax.YTick;
zt = Ax.ZTick;
Ax.Visible = 'off';
plot3([xt; xt], ones(2,numel(xt)).*[-1;1]*0.1, zeros(2,numel(xt)), '-k')
plot3(ones(2,numel(xt)).*[-1;1]*0.1, [yt; yt], zeros(2,numel(xt)), '-k')
plot3(ones(2,numel(xt)).*[-1;1]*0.1, zeros(2,numel(xt)), [zt; zt], '-k')
hold off
text(xt, zeros(size(xt)), zeros(size(xt)), compose(' %.1g',xt), 'Horiz','left', 'Vert','middle', 'Rotation',-35)
text(zeros(size(yt)), yt, zeros(size(yt)), compose(' %.1g',yt), 'Horiz','left', 'Vert','middle', 'Rotation',30)
text(zeros(size(zt)), zeros(size(zt)), zt, compose(' %.1g',zt), 'Horiz','left', 'Vert','middle', 'Rotation',-10)
axis('equal')
.

Image Analyst on 11 Jun 2022
The usual way is
ax = gca;
ax.XAxisLocation = "origin";
ax.YAxisLocation = "origin";
However it doesn't seem to work for this 3-D plot. Not sure why. It does work for 2-D plots though.
Atom on 11 Jun 2022
Edited: Atom on 11 Jun 2022
No..it is not working