sweep meshing
 

My assembly has got a number of different parts imported from solidworks, ansys meshing shows them as sweepable if they are not formed into a single part in design modeller, but if i form them as one part, then they are not shown as sweepable, i have tried slicing the body as well in design modeller but it still doesnt help, any ideas? i am thinking it might actually be a bug?

Its not a bug for sure. Have you tried manually selecting source and target faces for sweeping?