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Color a sphere surface/polar plot axis-wise

Asked by Jon Legarreta on 12 May 2016
Latest activity Commented on by Jon Legarreta on 12 May 2016
Hi there,
I would like to produce both a sphere and a polar plot whose surface color is defined at each XYZ axis as follows:
Top-bottom (Z) = blue
Left-right (Y) = red
Anterior-posterior (X) = green
The color in the boundaries/interfaces should be an interpolation of them.
Such as here:
and here (for the polar plot):
I have been googling for a while but did not find much help to do it.
Thanks,
Jon
PS: Similar questions seem to have been asked previously with a few variants, but the answers given seem not reproduce the figures pointed above.

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1 Answer

Answer by Mike Garrity
on 12 May 2016

Something like this, perhaps?
[x,y,z] = sphere(40);
col(:,:,1) = abs(y);
col(:,:,2) = abs(x);
col(:,:,3) = abs(z);
surf(x,y,z,col,'FaceColor','interp','EdgeColor','none')
axis equal
camlight
Here's a start on the "polar" one, but I'll let you add the grid & text.
view(2)
axis off
set(gca,'CameraUpVector',[1 0 0])
delete(findobj(gca,'Type','light'))

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Hi Mike,
thanks for your answer. Helps a lot !
I successfully added the sticks and the text to the sphere using
[X,Y,Z] = cylinder(cylinderRadius, cylinderResolution);
Z(2,:) = -(Z(1,:) + cylinderLength/2);
Z(1,:) = Z(1,:) + cylinderLength/2;
siStick = mesh(X,Y,Z,'FaceColor','b','EdgeColor','none');
yRotAx = [0 1 0]; % rotation around y-axis
rotate(lrStick, xRotAx, angle);
text(siStick.XData(1,1),siStick.YData(1,1),siStick.ZData(1,1) + offset,'S',...
'HorizontalAlignment','left','Color','b','FontSize',textSize);
Although it does not seem the easiest way, I did not find the way to do it thorough simpler transformations/functions.
As for the disc, I am having a hard time trying to mimic the way I set the text for the sphere case, and I am not succeeding.
Did not attempt the grid.
Any hints?
Thanks

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