Deciding what mesh element size to use
When generating the mesh you need to decide what element size to use. The maximum is 32.8 feet (10 meters).
To speed the analysis, it is useful to choose a coarse mesh for preliminary design and a fine mesh for final design.
A coarse mesh might have an element size of span length / 6. A fine mesh might have an element size of span length / 12. If in doubt, you should investigate the effects of different mesh element sizes.