Dear Firedrakers, I'm constructing a DG space on an extruded mesh. meshbase = RectangleMesh(Nx, Ny, Lx, Ly, quadrilateral=True) mesh = ExtrudedMesh(meshbase, Nz, Delta_z) horiz_elt = FiniteElement("DG", quadrilateral, 0) vert_elt = FiniteElement("DG", interval, 0) elt = OuterProductElement(horiz_elt, vert_elt) DG = FunctionSpace(mesh, elt) W=DG*DG Now I would like to impose Dirchlet BC on one of the boundaries. I tried bc0 = DirichletBC(W.sub(0), Expression("1.0e7"), 2,method="geometric") and get a ValueError: Geometric boundary conditions are not yet supported on extruded meshes Using the standard topological way, seems to have no effect at all. Is there a way around this? I would be fine with fixing the value on the most outer cell layer, if that is possible... Henrik -- Dipl.-Math. Henrik Büsing Institute for Applied Geophysics and Geothermal Energy E.ON Energy Research Center RWTH Aachen University ------------------------------------------------------ Mathieustr. 10 | Tel +49 (0)241 80 49907 52074 Aachen, Germany | Fax +49 (0)241 80 49889 ------------------------------------------------------ http://www.eonerc.rwth-aachen.de/GGE hbuesing@eonerc.rwth-aachen.de ------------------------------------------------------