plotting 2D slice of arbitrary orientation through 3D data in matplotlib
You can use roll function of numpy to rotate your plane and make it parallel with a base plane. now you can choose your plane and plot. Only problem is that at close to edges the value from one side will be added to opposite side.
I have a 3D regular grid of data.  I would like to write a routine allowing the user to specify a plane slicing through the data with arbitrary orientation and returning a contour plot of the data in the plane.  Is there a ready-made way in matplotlib to do this?  Could find anything in the docs.