Overlayd cells with multiple sections and constant cross-sections

[ewerthen]

Multiple Cells are going over 2 sections allthough they are defined correctly in the cpacs file: analytical_example_circ_beam_loads_composite_12_CPACS.zip

[joergbrech]

This is related to #933. Also a tolerance issue when the inner/outer borders coincide with the segment borders. This is a bug, bt similarly to the before-mentioned issue, a workaround is to move the cell borders slightly away from the segment borders.