Patch function - graphics objects:

The patch function is used to generate a patch graphics object, which is made from 2-dimensional polygons. The patch is defined by its vertices and faces. For illustration, consider a patch which has four vertices in 3-dimensional space, given by the coordinates:

(0, 0, 0)

(1, 0, 0)

(0, 1, 0)

(0.5, 0.5, 1)

Just to visualize these points first, the plot3 function is used, as shown in figure:

>> x = [0 1 0 0.5];

>> y = [0 0 1 0.5];

>> z = [0 0 0 1];

>> plot3(x,y,z,'ko')

Rotating the figure shows all four points, as shown in figure.

Generating and showing these points is not essential to generate a patch object; this was just complete to visualize at first the vertices . A patch object is defined by both the vertices and the faces of the polygon which connect these vertices. The one way of calling this function is patch(fv),here fv is a structure variable with fields known as vertices and faces.

polyhedron.vertices = [.  .  .

0 0 0

1 0 0

0 1 0

0.5 0.5 1];

polyhedron.faces = [.  .  .

1 2 3

1 2 4

1 3 4

2 3 4];

pobj = patch(polyhedron, .  .  .

'FaceColor',[0.8, 0.8, 0.8],.  .  .

'EdgeColor','black');