For those who are starting to work with Python this may be useful.

I have been trying to use VPython for a while with the Enthought distro to develop Python software. (I’m using 32 bit Python 2.7 Enthought distro for Mac OSX 10.6.8).

But for some reason the VPython package will not be installed if the Python distribution in your mac is not the official one (e.g. oficial Python 2.7 installed in /Library/Frameworks/Python.framework/Versions/2.7)

The Enthought distro installs itself in

/Library/Frameworks/Python.framework/Versions/Current

as a symbolic link to

/Library/Frameworks/Python.framework/Versions/7.2

Which is not right for VPython because it expects the default link to be ‘2.7’.

Ok, what I did was to delete the official 2.7 Python distro and create a symbolic link ‘2.7’ to the ‘7.2’ EDP version. And it works great!

To create the symbolic link just open the terminal and do:
>> cd /Library/Frameworks/Python.framework/Versions
>> sudo ln -s 7.2 2.7

Now open Python:
>> python

and type
from visual import *
sphere()

you should see a sphere draw like this:

Now Python works well with Enthought.

References
http://vpython.org/
http://www.enthought.com/