Why is plot3 slow when I use it in a loop?

I create plot3 in gui axes, if the number of elements that the many depictions of the process is very slow, if you can provide solutions

for i=1:length(AX(:,1))
   plot3(AX(i,:),AZ(i,:),AY(i,:),'-c','LineWidth',0.25);
   hold on
   plot3(AXD(i,:),AZD(i,:),AYD(i,:),'-g','LineWidth',0.5); 
end

Answer 1

[Andrew Newell]

You could try using line instead of plot3. You'll have to make sure all your options come in pairs, e.g.,

line(AX(i,:),AZ(i,:),AY(i,:),'LineStyle','-','Color','c','LineWidth',0.25);

See linespec for how to define each property.

EDIT: With the data you provided, I tried these commands and it worked fine.

for i=1:size(AX,2)
  line(AX(i,:),AZ(i,:),AY(i,:),'LineStyle','-', ...
'Color','c','Marker','.','LineWidth',1)
  line(AXD(i,:),AZD(i,:),AYD(i,:),'LineStyle','-', ...
'Color','g','Marker','.','LineWidth',1)
end

On my machine this is 4 times faster than using the code you provided. Note that when you use line the image is saved by default, so you don't need hold on.

[pink]

sorry andrew,

Error in ==>

main>undeformedbutton_Callback at 653

line

(AX(i,:),AZ(i,:),AY(i,:),'-g.','LineWidth',1);

[Andrew Newell]

line(AX(i,:),AZ(i,:),AY(i,:),'LineStyle','-','Color','g','Marker','.','LineWidth',1)

[pink]

??? Index exceeds matrix dimensions.

[Andrew Newell]

Are you saying that this error only occurs when you use line instead of plot3? Are you changing anything else besides the plot commands?

[Walter Roberson]

size(AX)

size(AZ)

size(AY)

size(AXD)

size(AZD)

size(AYD)

[pink]

AX =[ 0 2.1213;

4.2426 2.1213;

4.2426 2.1213;

0 2.1213]

AY =[ 0 4000;

0 4000;

0 4000;

0 4000]

AZ =[-4.2426 -2.1213;

-4.2426 -2.1213;

0 -2.1213;

0 -2.1213]

AXD =[ 0 2.0900;

4.2426 2.0900;

4.2426 2.0900;

0 2.0900]

AYD =[ 0 3.6818;

0 3.6818;

0 3.6818;

0 3.6818]

AZD =[4.2426 2.1849;

4.2426 2.1849;

0 2.1849;

0 2.1849]

[pink]

hi andrew

error occurred, if I change the "plot3"to "line"

[Andrew Newell]

See my revised answer.

[pink]

is work

sorry, but the picture does not fit what I want

[Andrew Newell]

What do you mean?

[pink]

object generated using the "plot3" not the same as using the "line"

Answer 2

[Walter Roberson]

You only need to execute the "hold on" once; after that it is set and becomes a waste of time.

At some point, you are going to exceed the amount of memory that your graphics card has easily available; things will slow down then.

You could experiment with switching renderers.

[pink]

hi, Walter

Can you give an example?

[Walter Roberson]

set(gcf,'Renderer','zbuffer')

[pink]

Calling AXES(h) without an output be can slow. Include 'h' in plot fucntion argument

[Walter Roberson]

Yes, that could help:

axh = gca;

plot3(axh, AX(1,:),AZ(1,:),AY(1,:),'-c','LineWidth',0.25);

hold(axh,'on')

plot3(axh,AXD(1,:),AZD(1,:),AYD(1,:),'-g','LineWidth',0.5);

for i = 2:length(AX,2)

plot3(axh,AX(i,:),AZ(i,:),AY(i,:),'-c','LineWidth',0.25);

plot3(axh,AXD(i,:),AZD(i,:),AYD(i,:),'-g','LineWidth',0.5);

end

[Walter Roberson]

Should be size(AX,1) instead of length(AX,2)

[pink]

AX =[ 0 2.1213;

4.2426 2.1213;

4.2426 2.1213;

0 2.1213]

AY =[ 0 4000;

0 4000;

0 4000;

0 4000]

AZ =[-4.2426 -2.1213;

-4.2426 -2.1213;

0 -2.1213;

0 -2.1213]

AXD =[ 0 2.0900;

4.2426 2.0900;

4.2426 2.0900;

0 2.0900]

AYD =[ 0 3.6818;

0 3.6818;

0 3.6818;

0 3.6818]

AZD =[4.2426 2.1849;

4.2426 2.1849;

0 2.1849;

0 2.1849]