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#### 15.2.2.3 Three-dimensional Geometric Shapes

: cylinder
: cylinder (r)
: cylinder (r, n)
: cylinder (hax, …)
: [x, y, z] = cylinder (…)

Plot a 3-D unit cylinder.

The optional input r is a vector specifying the radius along the unit z-axis. The default is [1 1] indicating radius 1 at `Z == 0` and at `Z == 1`.

The optional input n determines the number of faces around the circumference of the cylinder. The default value is 20.

If the first argument hax is an axes handle, then plot into this axes, rather than the current axes returned by `gca`.

If outputs are requested `cylinder` returns three matrices in `meshgrid` format, such that `surf (x, y, z)` generates a unit cylinder.

Example:

```[x, y, z] = cylinder (10:-1:0, 50);
surf (x, y, z);
title ("a cone");
```

: sphere ()
: sphere (n)
: sphere (hax, …)
: [x, y, z] = sphere (…)

Plot a 3-D unit sphere.

The optional input n determines the number of faces around the circumference of the sphere. The default value is 20.

If the first argument hax is an axes handle, then plot into this axes, rather than the current axes returned by `gca`.

If outputs are requested `sphere` returns three matrices in `meshgrid` format such that `surf (x, y, z)` generates a unit sphere.

Example:

```[x, y, z] = sphere (40);
surf (3*x, 3*y, 3*z);
axis equal;
```

: ellipsoid (xc, yc, zc, xr, yr, zr, n)
: ellipsoid (…, n)
: ellipsoid (hax, …)
: [x, y, z] = ellipsoid (…)

Plot a 3-D ellipsoid.

The inputs xc, yc, zc specify the center of the ellipsoid. The inputs xr, yr, zr specify the semi-major axis lengths.

The optional input n determines the number of faces around the circumference of the cylinder. The default value is 20.

If the first argument hax is an axes handle, then plot into this axes, rather than the current axes returned by `gca`.

If outputs are requested `ellipsoid` returns three matrices in `meshgrid` format, such that `surf (x, y, z)` generates the ellipsoid.