OpenLB – Open Source Lattice Boltzmann Code › Forums › on OpenLB › General Topics › STL File not valid › Reply To: STL File not valid April 13, 2020 at 12:02 pm #4921 sthavishthaParticipant Dear iJokerify You must place the cylinder3d.stl file (available in the /examples/laminar/cylinder2d/ folder) in the folder where you run your code. Regards Sthavishtha