Continuous 3D plotting (i.e. figure update) using python-matplotlib?


Question

I have a simulation which calculates surface data for each iteration of the simulation. I would like to continuously plot that data as a surface plot to the same window (updating the plot in each iteration) in order to see how it evolves and to check the algorithm.

My Idea was to create a class that would initialize the window/plot and then redraw to that window from inside the simulation loop. Here is the class I came up with:

import numpy as np
import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D
from matplotlib import cm
from matplotlib.ticker import LinearLocator, FixedLocator, FormatStrFormatter
import matplotlib
matplotlib.interactive( False )

class plot3dClass( object ):

    def __init__( self, systemSideLength, lowerCutoffLength ):
        self.systemSideLength = systemSideLength
        self.lowerCutoffLength = lowerCutoffLength
        self.fig = plt.figure()
        self.ax = self.fig.add_subplot( 111, projection='3d' )
        self.ax.set_zlim3d( -10e-9, 10e9 )

        X = np.arange( 0, self.systemSideLength, self.lowerCutoffLength )
        Y = X
        self.X, self.Y = np.meshgrid(X, Y)

        self.ax.w_zaxis.set_major_locator( LinearLocator( 10 ) )
        self.ax.w_zaxis.set_major_formatter( FormatStrFormatter( '%.03f' ) )

        heightR = np.zeros( self.X.shape )
        self.surf = self.ax.plot_surface( self.X, self.Y, heightR, rstride=1, cstride=1, cmap=cm.jet, linewidth=0, antialiased=False )
        #~ self.fig.colorbar( self.surf, shrink=0.5, aspect=5 )

        plt.show()


    def drawNow( self, heightR ):

        self.surf = self.ax.plot_surface( self.X, self.Y, heightR, rstride=1, cstride=1, cmap=cm.jet, linewidth=0, antialiased=False )
        plt.draw()                      # redraw the canvas

        time.sleep(1)

The problem I have with this code, is that the code stops at the 'plt.show()' and only continues, when I close the plot-window. Also I am not sure if the calls of 'self.ax.plot_surface( ... )' and 'plt.draw()' would update the figure as I would like it.

So is this class the right direction?

If yes: What modifications are needed?

If not: Could somebody please give me advice how to achieve what I want?

I realize that this problem might seem trivial to others, but I (honestly) did spend the whole day yesterday on Google and trying and I'm at a loss...

Any help would greatly appreciated, so that I can get back to my actual work.

Tanks alot in advance.

As a reference:

I also found the following code which does, what I want, but it is in 2D, so it does not help me directly:

from pylab import *
import time

ion()

tstart = time.time()               # for profiling
x = arange(0,2*pi,0.01)            # x-array
line, = plot(x,sin(x))

for i in arange(1,200):
    line.set_ydata(sin(x+i/10.0))  # update the data
    draw()                         # redraw the canvas

print 'FPS:' , 200/(time.time()-tstart)
1
10
10/19/2013 3:52:02 PM

You do not need to plt.show() if it is an animated (interactive) plot. You also want interactive set to True, not False which is the same as calling ion() in your 2d example. Also, you need to remove() the surface plots from previous frames if you do not want to see them all.

Otherwise you were pretty close.

This works for me:

import numpy as np
import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D
from matplotlib import cm
from matplotlib.ticker import LinearLocator, FixedLocator, FormatStrFormatter
import matplotlib, time

class plot3dClass( object ):

    def __init__( self, systemSideLength, lowerCutoffLength ):
        self.systemSideLength = systemSideLength
        self.lowerCutoffLength = lowerCutoffLength
        self.fig = plt.figure()
        self.ax = self.fig.add_subplot( 111, projection='3d' )
        self.ax.set_zlim3d( -10e-9, 10e9 )

        rng = np.arange( 0, self.systemSideLength, self.lowerCutoffLength )
        self.X, self.Y = np.meshgrid(rng,rng)

        self.ax.w_zaxis.set_major_locator( LinearLocator( 10 ) )
        self.ax.w_zaxis.set_major_formatter( FormatStrFormatter( '%.03f' ) )

        heightR = np.zeros( self.X.shape )
        self.surf = self.ax.plot_surface( 
            self.X, self.Y, heightR, rstride=1, cstride=1, 
            cmap=cm.jet, linewidth=0, antialiased=False )
        # plt.draw() maybe you want to see this frame?

    def drawNow( self, heightR ):
        self.surf.remove()
        self.surf = self.ax.plot_surface( 
            self.X, self.Y, heightR, rstride=1, cstride=1, 
            cmap=cm.jet, linewidth=0, antialiased=False )
        plt.draw()                      # redraw the canvas
        time.sleep(1)

matplotlib.interactive(True)

p = plot3dClass(5,1)
for i in range(2):
    p.drawNow(np.random.random(p.X.shape))
8
3/3/2011 7:22:54 PM

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