`cylinder`

Generates the coordinates of a surface of revolution, by default a cylinder.

Syntax

[X, Y, Z] = cylinder

A unit cylinder with 20 points around the circumference.

[X, Y, Z] = cylinder(r)

Revolves the radius profile r along a unit height.

[X, Y, Z] = cylinder(r, n)

Uses n points around the circumference.

cylinder(___)

With no output arguments, draws the surface.

Description

The profile vector r gives the radius at heights equally spaced between 0 and 1. A scalar r is treated as [r r], producing a straight cylinder, while [2 1] gives a cone frustum and [0 1] a cone. The matrices can be passed to surf or mesh; the seam column is repeated so the surface closes.

Input arguments

r: Scalar radius or vector of radii at equally spaced heights from 0 to 1.
n: Number of points around the circumference, 20 by default.

Output arguments

X, Y, Z: Matrices of size numel(r) by n+1; row k is the circle at height Z(k,1).

Example

A vase profile

r = [1 1.4 1 0.6 1];
[X, Y, Z] = cylinder(r, 12);
disp(size(X))
disp(Z(:, 1)')
surf(X, Y, Z)

Output

     5    13
         0    0.2500    0.5000    0.7500    1.0000

cylinder