contour3 — Create 3-D contour line plots in MATLAB and RunMat.

contour3 creates 3-D contour line plots from scalar fields. It accepts core contour-style inputs but places each isoline at its scalar Z level rather than projecting onto a flat plane.

Syntax

contour3(Z)

How contour3 works

• contour3(Z) uses implicit X and Y axes derived from the Z matrix shape.
• contour3(X, Y, Z) accepts explicit vector axes or meshgrid-style X and Y matrices.
• A scalar fourth argument selects the number of contour levels; a vector fourth argument selects exact contour levels.
• LineSpec color tokens such as 'k' and name-value pairs such as 'LineWidth' are accepted.
• GPU-aware contour generation is used when the shared plotting path can operate directly on GPU-resident scalar fields.

Options

• 'LevelList' / 'Levels' accepts an explicit, strictly increasing vector of contour values.
• 'LevelStep' specifies the spacing between generated contour levels.
• 'LineColor' accepts MATLAB color strings, RGB triples, 'auto', and 'none'.
• 'LineWidth' controls contour line thickness.

GPU memory and residency

contour3 preserves GPU residency when the shared WGPU plotting context can consume the Z buffer directly. If that path is unavailable, RunMat gathers once and builds the same contour geometry on the CPU.

Examples

Create a basic 3-D contour plot

[X, Y] = meshgrid(-2:0.25:2, -2:0.25:2);
Z = X .* exp(-X.^2 - Y.^2);
contour3(X, Y, Z);

Use explicit contour levels with high-contrast lines

[X, Y] = meshgrid(linspace(-3, 3, 80), linspace(-3, 3, 80));
Z = sin(X) .* cos(Y);
contour3(X, Y, Z, [-0.75 -0.25 0.25 0.75], 'Color', [0.05 0.35 0.95], 'LineWidth', 2.25);
zlabel('Potential');
view(45, 30);

Inspect the returned contour handle

Z = peaks(40);
h = contour3(Z, 12, 'Color', [0.9 0.2 0.05], 'LineWidth', 2.0);
get(h, 'Type')

Expected output:

ans =
    'contour'

Rendered contour3 example

[X, Y] = meshgrid(linspace(-3, 3, 100), linspace(-3, 3, 100));
Z = sin(X).*cos(Y) + 0.25*cos(2*X + Y);
levels = [-0.9 -0.6 -0.3 0 0.3 0.6 0.9];

contour3(X, Y, Z, levels, 'LineWidth', 2);
title('Potential Field Levels');
xlabel('x');
ylabel('y');
zlabel('Potential');
view(42, 28);
grid on;

Compare this result with other chart types in the MATLAB Plot Gallery.

Using contour3 with coding agents

Open a RunMat example with live inputs, then ask the agent to explain how contour3 changes the result.

FAQ

Related Plotting functions

More plotting resources

• Plot replay and export

Open-source implementation

Unlike proprietary runtimes, every RunMat function is open-source. Read exactly how contour3 is executed, line by line, in Rust.

• View the source for contour3 in Rust on GitHub
• Learn how the RunMat runtime works
• Found a bug? Open an issue with a minimal reproduction.

About RunMat

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