CODEWITHSUNDEEP
matlabplot3dmeshpoint-clouds
Meta Fan
Meta Fan

Reputation: 1585

How to plot a 3D triangle mesh shape with a specific colormap in MATLAB?

A 3D triangle mesh shape is represented by vertices and triangle faces. For example, shape in matlab which has shape.X, shape.Y, shape.Z(the vertices) and shape.TRIV(the triangle faces) can be seen as a 3D triangle mesh shape.

My question is how to visualize such a shape in MATLAB with a specific colormap.

(for example, the colormap can be defined as a distance vector of length(shape.X) whose elements are Euclidean distances of all vertices to a single vertex M, in this situation, the cooler colors related to the smaller distances, and the hotter colors related to the larger distances.)

Upvotes: 0

Views: 970

Answers (2)

Meta Fan
Meta Fan

Reputation: 1585

Based on @Suever's answer, I add some extra code to make the shape plot smoother and add a camera light. By the way, if the shape is a point cloud without faces, it's better to choose scatter3 instead of plot3.

vertices = cat(2, shape.X(:), shape.Y(:), shape.Z(:));

%// Compute distance of each vertex from the origin
distances = sqrt(sum(bsxfun(@minus, vertices, [0 0 0]).^2, 2)); 

%// Create the patch object
h = patch('Vertices', vertices, 'Faces', shape.TRIV);

%// Set the vertex colors and use interpolation to shade the faces
set(h, 'FaceColor', 'interp', 'FaceVertexCData', distances,'EdgeColor', 'none');
%or use shading interp instead of setting 'EdgeColor'=='none' to make the shape smooth;

%// Scale the color limits to your data
set(gca, 'clim', [min(distances(:)), max(distances(:))])

% add a colorbar
colorbar

% change the colormap
colormap(jet(64))

%use the same unit length along each axis  and fit the axes box tightly around the data.
axis image 

% turn off the coordinate
axis off

% set the camlight strength, trial and error
set(h, 'AmbientStrength',0.25, 'SpecularStrength',0.0,'DiffuseStrength',0.5);
lighting phong;
camlight left; %left,right,head
set(gcf,'Renderer','opengl');  %‘opengl’,'zbuffer'

If it's a point cloud：

h2=scatter3(X,Y,Z,'.');
view([0,90]);
h2.CData=distances;
axis image;
set(gca, 'clim', [min(distances(:)), max(distances(:))]);
colormap(jet(64));

Upvotes: -1

Suever
Suever

Reputation: 65460

You can use a patch object to show your 3D shape and then use the FaceVertexCData and FaceColor properties of the resulting patch to set a value which can automatically be mapped to the axes color limits.

vertices = cat(2, shape.X(:), shape.Y(:), shape.Z(:));

%// Create the patch object
h = patch('Vertices', vertices, ...
          'Faces', shape.TRIV);

%// Compute distance of each vertex from the origin
distances = sqrt(sum(bsxfun(@minus, vertices, [0 0 0]).^2, 2));

%// Set the vertex colors and use interpolation to shade the faces
set(h, 'FaceColor', 'interp', ...
       'FaceVertexCData', distances);

%// Scale the color limits to your data
set(gca, 'clim', [min(distances(:)), max(distances(:))])

Upvotes: 5

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