Btukfyl

I try to make an animation using matplotlib and fail at the first step. I cannot even make a moving cube. I created six surface by using the plot_surface method but I cant move them precisely. I have two questions:

1. 
   

   How to move a Poly3DCollection object.

   
   
   

   The method I tried is using set_offsets provided by the collection class.
   But this method can only set x and y and the unit is weird.
   For example, I create a cube at (1, 0 ,0) and invoke set_offsets([100, 0]),
   the horizontal position of the plotted cube is approximately 1.4. I try to link this unit to the dpi of the figure object but failed.

   
   



2. What are the units for my data, the line width, and the set_offsets method.

My current code is as follows:

    # -*- coding: utf-8 -*-

    from mpl_toolkits.mplot3d import Axes3D

    import matplotlib.pyplot as plt



    fig = plt.figure()

    ax = fig.gca(projection='3d')

    ax.set_aspect("equal")

    plt.xlabel('x')

    plt.ylabel('y')



    class cube():



      def __init__(self, ax, x = 0, y = 0, z = 0,

        height = 1., width = 1., depth = 1.) :



        self.ax = ax

        self.initiate(ax, x, y, z, height, width, depth)



      def initiate(self, ax, x = 0, y = 0, z = 0,

        height = 1., width = 1., depth = 1.) :



        self.ax = ax

        self.x, self.y, self.z = x, y, z

        self.height, self.width, self.depth = height, width, depth



        X = [[x, x + width], [x, x + width]]

        Y = [[y, y], [y, y]]

        Z = [[z, z], [depth, depth]]

        self.top = ax.plot_surface(X, Y, Z, linewidth=1, edgecolors='black', shade=False, color = 'red')



        X = [[x, x + width], [x, x + width]]

        Y = [[y + height, y + height], [y + height, y + height]]

        Z = [[z, z], [depth, depth]]

        self.bottom = ax.plot_surface(X, Y, Z, linewidth=1, edgecolors='black', shade=False, color = 'red')



        X = [[x, x + width], [x, x + width]]

        Y = [[y, y], [y + height, y + height]]

        Z = [[z, z], [z, z]]

        self.front = ax.plot_surface(X, Y, Z, linewidth=1, edgecolors='black', shade=False, color = 'green')



        X = [[x, x + width], [x, x + width]]

        Y = [[y, y], [y + height, y + height]]

        Z = [[depth, depth], [depth, depth]]

        self.back = ax.plot_surface(X, Y, Z, linewidth=1, edgecolors='black', shade=False, color = 'green')



        X = [[x, x], [x, x]]

        Y = [[y, y + height], [y, y + height]]

        Z = [[z, z], [depth, depth]]

        self.left = ax.plot_surface(X, Y, Z, linewidth=1, edgecolors='black', shade=False, color = 'blue')



        X = [[x + width, x + width], [x + width, x + width]]

        Y = [[y, y + height], [y, y + height]]

        Z = [[z, z], [depth, depth]]

        self.right = ax.plot_surface(X, Y, Z,

          linewidth=1, edgecolors='black', shade=False, color = 'blue')



      def set_location(self, x, y, z) :

        c.front.set_offsets([x, y])

        c.back.set_offsets([x, y])

        c.left.set_offsets([x, y])

        c.right.set_offsets([x, y])

        c.top.set_offsets([x, y])

        c.bottom.set_offsets([x, y])



    c = cube(ax, 1, 0, 0)

    print type(c.left)

    c.set_location(100, 0, 0)

    plt.show()

According to the PolyCollection documentation, the offsets are applied in screen coordinates by default. To move your objects in data coordinates, first call set_offset_position('data') for each of your objects, e.g.

self.top.set_offset_position('data')