multiple objects on the same plot (MATPLOTLIB)

Question

SHORT QUESTION: I'd like to draw different shapes using winged egde strucutre, so I have one class that actually draw any winged eged and another to define a cube and other shapes. Now I want to draw 2 cubes on the same figure but I can't and I always get one cube in each figure.

LONG QUESTION: I'd like to draw different shapes using winged egde strucutre, so I have:

class WEdge -> wedge_instance = WEdge(vertices, faces) 

and then I have one class for each shape that I need to draw for example:

class Box -> simplebox = Box(vertices, faces, translation, rotation)

In the WEdge class I actually plot the objects using the following code:

        ax = a3.Axes3D(pl.figure())
        for k in range(self.nFaces):
           currentColumn = self.faces[k,:]
           vtx = np.zeros([4,3])
           j = 0
           for i in currentColumn:
               vtx[j] = self.vertices[i-1]
               j = j +1
        tri = a3.art3d.Poly3DCollection([vtx])
        tri.set_color(colors.rgb2hex(sp.rand(3)))
        tri.set_edgecolor('b')
        ax.add_collection3d(tri)  

The problem is when I want to draw two cube in the same figure. I have tried many possible combinations of hold, gca and so on but in the end I get always one cube in Figure 1 and the other in Figure 2.

Example:

>>>Box(3,1,3, [0,1,0], np.eye(3))
>>> # hold, gca, timer...
>>>Box(3,1,3, [1,0,3], np.eye(3))

Answer 1

Don't define a new axis for each "structure":

    ax = a3.Axes3D(pl.figure())

Pass ax into the WEdge class, so they can all draw on the same axis:

def init(self, ..., ax=None):
    self.ax = ax if ax else a3.Axes3D(pl.figure())

we1 = WEdge()
we2 = WEdge(ax=we1.ax)

or perhaps more egalitarian,

ax = a3.Axes3D(pl.figure())
we1 = WEdge(ax)
we2 = WEdge(ax)

You may need to also pass ax to your cube class too.