Problem with getframe with trisurf when making movie

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Renbo 2014-9-16

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/155107-problem-with-getframe-with-trisurf-when-making-movie

评论： Renbo 2014-9-22

I want to make a movie use getframe and VideoWriter to view a 3D dataset at different view angle. First, i use scatter3 to plot 3D dataset, and use getframe and VideoWriter. It works perfect. However, when i use trisurf to plot the surface of dataset,and use exactly the same code to as above. But i found the the frame in this movie does not change over time, and it is a 2D image instead of 3D.

Are there some meet the same problem? Many thanks.

writerObj = VideoWriter('ColorGamutDTri.avi');
writerObj.FrameRate = 80;
open(writerObj);
n=-180;
while(n<180)
     view(n,10);
     n=n+1;
     pause(0.1);
     frame = getframe(gcf); 
     writeVideo(writerObj, frame);
end
close(writerObj);

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Geoff Hayes 2014-9-19

在 MATLAB Online 中打开

Renbo - please clarify I indeed got the same result as you got. No rotation in movie at all because I did see the rotation when I ran the example from the trisurf link with your above code.

 [x,y] = meshgrid(1:15,1:15);
 tri = delaunay(x,y);
 z = peaks(15);
 trisurf(tri,x,y,z);
 writerObj = VideoWriter('ColorGamutDTri.avi');
 writerObj.FrameRate = 80;
 open(writerObj);
 n=-180;
 while(n<180)
    view(n,10);
    n=n+1;  
    pause(0.1);
    frame = getframe(gcf);
    writeVideo(writerObj, frame);
 end
close(writerObj);

On the video that you have created, type the following in the Command Window

 obj = VideoReader('ColorGamutDTri.avi');
 get(obj)

which will return information like

General Settings:
  Duration = 4.5
  Name = ColorGamutDTri.avi
  Path = /Users/geoff/Development/bitbucket_repos/matlab/testing
  Tag = 
  Type = VideoReader
  UserData = []
Video Settings:
  BitsPerPixel = 24
  FrameRate = 80
  Height = 420
  NumberOfFrames = 360
  VideoFormat = RGB24
  Width = 560

What do you see for the NumberOfFrames for your video? (The above output was taken from the above code pasted in this comment.)

Renbo 2014-9-21

编辑：Renbo 2014-9-21

在 MATLAB Online 中打开

Hi Geoff, Sorry for the confusion and thanks for the detailed answers.

1. I run your code, and i get the 'perfect' video. The figure in the video is rotating.

2. However, when i was running my own data as attached LabCCDT.mat, though i can get a video and the length looks norm, but the figure did not rotate as it did in Matlab.

3. Could you run two trisurf plots in the same figure, it seems that the figure in the video does not rotate.

I attached the code you provided and my own data, thanks for you help.

figure;

   % load ('LabCCDT.mat');
   % XYZ = LabCCDT;
    XYZ = randn(100,3);
    tri = delaunay(XYZ);
    H1 = trisurf(tri,XYZ(:,1),XYZ(:,2),XYZ(:,3),'facecolor', 'b',   'edgecolor','b');
    hold on;
    XYZ2 = randn(200,3);
    tri2 = delaunay(XYZ2);
    z2 = peaks(20);
    H2= trisurf(tri2,XYZ2(:,1),XYZ2(:,2),XYZ2(:,3),'facecolor', 'r', 'edgecolor','r');
    hold off;
    writerObj = VideoWriter('ColorGamutDTri.avi');
    writerObj.FrameRate = 80;
    open(writerObj);
    n=-180;
    while(n<180)
        view(n,10);
        n=n+5;
        pause(0.1);
        frame = getframe(gcf);
        writeVideo(writerObj, frame);
    end
    close(writerObj);