Quote Originally Posted by mike mcdermid View Post
what did you hand calculations come up with?? for the 6m slab
Not done them by hand for the slab, its too difficult. But fixed the issue... as i suspected its in the STL export from Sketchup... you have to export in millimetres and not metres as it gets the sizing wrong in some way. Its clearly not obvious as if all the measurements were out by 1000 it would have been a 6mm beam of .3mm sq cross section and that clearly couldnt have a 353mm deflection... anyway it's working so now I'm back to my original model...