Show 3D model

Models composed of triangle meshes are commonly used in art, engineering, and medical CAD for representing 3D objects. These models consist of a series of triangles in 3D space, sometimes also including colors. Plotting them is not difficult, but it is tedious because the structures are composed of faces (triangles) are defined as indices into vertices (3D points). I wrote the function 'show_model' as a simple plot tool analogous to 'plot'. It can handle variable arguments in to specify transparency, face color, and line style. It returns a handle to the patch object that is created.

Usage:
h = show_model(model,varargin)

Example (with 2d triangles):
model.v = [2 4; ... % x-y coords
2 8; ...
8 4; ...
8 0; ...
0 4; ...
2 6; ...
2 2; ...
4 2; ...
4 0; ...
5 2; ...
5 0 ];
% order in which vertices are joined to form triangles
model.f = [1 2 3; ...
1 3 4; ...
5 6 1; ...
7 8 9; ...
11 10 4];
model.c=[zeros(size(model.v,1),3)];
show_model(model)