# Visualise 3D trajectory data as a volume plot

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Impala on 26 Jul 2018
Commented: Impala on 27 Jul 2018
I have 3D trajectory data (x, y, z coordinates) which I would like to visualise as a volume plot. I'm using plot3 but just getting a line plot - see attached pdf with images of what I'm getting using plot3 and what I would like to get.
I've also attached a .mat file containing my 3D-trajectory data.
KSSV on 26 Jul 2018
Edited: KSSV on 26 Jul 2018
Huumhh..it looks complex for me.....Do you need to remove some points? There is difference in the line plot and the plot you wanted..
Impala on 26 Jul 2018
Yes, points can be removed - its just for visualisation purposes.
I have read posts on similar topics but haven't been successful so far. I'm getting stuck on the bit where I need to transform my 3D trajectory data into a form that the matlab volume visualisation tools can use as inputs.

KSSV on 26 Jul 2018
Edited: KSSV on 27 Jul 2018
Check the below trial code:
x = S.xSmooth ;
y = S.ySmooth ;
z = S.zSmooth ;
x = x(1:5:end) ; y = y(1:5:end) ; z = z(1:5:end) ;
N = [diff(x) diff(y) diff(z)] ;
C = 20*ones(size(x)) ;
figure
hold on
plot3(x,y,z,'r')
Cx = zeros([],[]) ;
Cy = zeros([],[]) ;
Cz = zeros([],[]) ;
for i = 1:1:length(x)-1
center = [x(i) y(i) z(i)] ;
normal = [N(i,1) N(i,2) N(i,3)] ;
Cx(i,:) = P(1,:);
Cy(i,:) = P(2,:);
Cz(i,:) = P(3,:);
end
h = mesh(Cx,Cy,Cz) ; shading interp
h.FaceAlpha = 0.5 ;
KSSV on 27 Jul 2018
Edited the code...:)
Impala on 27 Jul 2018
This works really well :) thank you so much! One last question - how do I get it to be the same colour throughout and also a little transparent so I can see the line plot through it? I've tried modifying the h.FaceColor and h.FaceAlpha values but it's not doing anything.