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

()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) ;

[Jan]

What do you call "axes"? In Matlab this is the complete object, which contains the drawn objects, X,Y,Z-axes and titles. Do you want to draw a tripod for the labled axes from the center, or do you want to see only one octant of the 3D space?

What do you call "interiors"?

[Atom]

I want to draw a tripod for the labled axes from the center

[Jan]

And the "interiors"?

[Image Analyst]

I guess he wants just the convex hull points, like from convhulln

[Atom]

The interior is like as the post of Image Analyst (convhulln)

Answer 1

[Star Strider]

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')

.

Answer 2

[Image Analyst]

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]

No..it is not working