How can I represent points and lines in 3 dimensions?

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종수 허
종수 허 am 16 Mai 2022
Kommentiert: 종수 허 am 17 Mai 2022
ox=0; oy =0; oz=0;
x1=0; y1 =0; z1=0;
x2=0; y2 =0; z2=0;
x3=2; y3 =0.6; z3=0;
x4=2; y4 =0.3; z4=0;
x5=2; y5 =0.3; z5=-0.7;
x6=2; y6 =0.3; z6=-0.7;
hold on;
x = [ox x1 x2 x3 x4 x5 x6]; % a matrix of dots
y = [oy y1 y2 y3 y4 y5 y6];
z = [oz z1 z2 z3 z4 z5 z6];
plot3(x,y,z,'ok') %plot points on a graph
plot3([ox, x1],[oy, y1],[oz, z1], 'r') %to connect dots and lines
plot3([x1, x2],[y1, y2],[z1, z2], 'g')
plot3([x2, x3],[y2, y3],[z2, z3], 'b')
plot3([x3, x4],[y3, y4],[z3, z4], 'c')
plot3([x4, x5],[y4, y5],[z4, z5], 'm')
plot3([x5, x6],[y5, y6],[z5, z6], 'y')
grid
max_L = 3;
axis([-max_L max_L -max_L max_L -max_L max_L]);
If I draw like this, it will appear in 2D instead of 3D. How can I represent it in 3D?

Akzeptierte Antwort

DGM
DGM am 16 Mai 2022
Bearbeitet: DGM am 16 Mai 2022
Either move the hold on statement after the first call to plot3(), or issue a
view(3)
command after plotting.
Creating a pile of named variables only leads to problems. Imagine if you wanted to do this with 100 points. With the following example, the code doesn't have to be scaled with the number of points. All you need to do is generate a new colormap of the appropriate length.
% just the points
x = [0 0 0 2 2 2 2];
y = [0 0 0 0.6 0.3 0.3 0.3];
z = [0 0 0 0 0 -0.7 -0.7];
plot3(x,y,z,'ok') %plot points on a graph
hold on;
% rearrange into a series of segments
x = repelem(x,1,2);
x = reshape(x(2:end-1),2,[]).';
y = repelem(y,1,2);
y = reshape(y(2:end-1),2,[]).';
z = repelem(z,1,2);
z = reshape(z(2:end-1),2,[]).';
plot3(x,y,z) %to connect dots and lines
% apply whatever colormap you want to the series of line segments
cmap = hsv(6);
cmap = cmap([1 3 5 4 6 2],:); % to get the same order you used
set(gca,'colororder',cmap)
grid
max_L = 3;
axis([-max_L max_L -max_L max_L -max_L max_L]);
  4 Kommentare
DGM
DGM am 16 Mai 2022
Consider the example:
x = 1:10
x = 1×10
1 2 3 4 5 6 7 8 9 10
x = repelem(x,1,2);
x = reshape(x(2:end-1),2,[]).'
x = 9×2
1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10
Each row becomes a line object.
종수 허
종수 허 am 17 Mai 2022
thank you. My question has been resolved !!!!

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KSSV
KSSV am 16 Mai 2022
It is in 3D, you need to change the view.
view(3)

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