On Thu, Sep 29, 2011 at 4:31 PM, Holger Brandsmeier <holger.brandsmeier@sam.math.ethz.ch> wrote:
Hi Ben,

in your example
> http://matplotlib.sourceforge.net/examples/mplot3d/polys3d_demo.html
the essential line is:
 ax.add_collection3d(poly, zs=zs, zdir='y')
according to everything I see this can only draw something that is
made out of several axes parallel parts. I don't think how with such a
command you could end up with some picture like:

That is correct.  It is only for simple conversions.

What I want to plot should look like that picture (with is part of
your gallery), just that I don't have a meshgrid data underlying.

That is why you have to work with the 3D objects from mpl_toolkits.mplot3d.art3d directly.  There isn't a lot of documentation, so your best bet is to look at the source code of the module.
Your second example seems to have the same limitation
just it works with the command
 art3d.pathpatch_2d_to_3d(p, z=0, zdir="x")

The only way that I currently see is that I call
for each quadrilateral of my mesh.

That would be overkill.  However, try checking out the source code for plot_surface() to see how it creates its Poly3DCollection object.

Ben Root