# Re: Geometry – Example “MultiComponentXd”

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Hello Ivan,rnrnThe SuperGeometry of the problem is the original geometry extended with an overlap of 2. So the cuboid with material number 1 is larger than you assume. Use a visualization software as for exampleparaview (www.paraview.com) and visualize the geometry to see the material numbers.rnIf you do so, you see, material numbers are set correctly for nx = 30. rnThere is no “”fluid flow”” as you call it, because of the physical properties of the problem. There are periodic boundary conditions and therefore depending of the length of nx, the periodicity keeps the solution kind of stationary.rnrn>>> When a 400×200 nodes Lattice is set, what does it mean to have something like “”origin1[0]=-2″”? Does it mean this node is two nodes left distant the first one (which I assume is on the left bottom of the lattice)?rnrnThis is because of the overlap (=2) set for the SuperGeometry generation. The given origin for the original CuboidGeometry is (0,0,1).rnrn>> If so, why was used -2 instead of -1 or 0? rnrnThe overlap is 2.rnrn>> And why nx+3 instead of nx-origin (in this example, nx+2)?Why do we need those extra nodes before and after the lattice which don not seem to be part of it?rnrnThe extend is added to the origin, therefore the complete length is nx=4.rnrnI hope I could help you! rnrnmlm