Matlab Graphics - 3D Plots

Meshgrid

meshgrid is an essential function to create 2D grids of coordinates for 3D plots.

% For existing x and y
[X, Y] = meshgrid(x, y);
% Squre grid
[x, y] = meshgrid(-10:0.5:10);

Where:

• x is a vector specifying the x-coordinates of the grid points.
• y is a vector specifying the y-coordinates of the grid points.
• X and Y are output matrices representing the 2D grid of coordinates, where X holds the x-coordinates of each point in the grid, and Y holds the y-coordinates of each point in the grid.

Plots

surf & mesh

% Create a grid of x and y values
[x, y] = meshgrid(-10:0.5:10);
 
% Compute z values using the function
z = sin(sqrt(x.^2 + y.^2));
 
% Create a figure and plot the surface
f = figure;
% surf(x, y, z);
% mesh(x, y, z);
contour(x, y, z);
 
% Add labels and title
xlabel('X-axis');
ylabel('Y-axis');
zlabel('Z-axis');
title('Surface Plot of z = sin(sqrt(x^2 + y^2))');
waitfor(f)

surf

• Notice that the data function should use element-wise operations

scatter3

A scatter3 plot is used to visualize individual data points in 3D space. Let’s create a scatter3 plot for randomly generated data points.

% Generate random data
n = 100;
x = randn(n, 1);
y = randn(n, 1);
z = randn(n, 1);
 
% Create a figure and plot the scatter points
figure;
scatter3(x, y, z, 'filled', 'MarkerFaceColor', 'b');
 
% Add labels and title
xlabel('X-axis');
ylabel('Y-axis');
zlabel('Z-axis');
title('Scatter3 Plot of Random Data Points');

View

In MATLAB, you can copy the rotation status of a 3D graph (e.g., a 3D plot or a mesh plot) from one figure to another using the view function. The view function allows you to set the azimuth and elevation angles, which control the rotation status of the 3D graph.

% Set the desired view angles for the 3D graph in the first figure
azimuth = 30;
elevation = 25;
view(azimuth, elevation);
 
% Get the current view angles from the first figure
[azimuth, elevation] = view;