Creating slabs from inclined beams

i want to create the slabs from the existing beams, (from the center line of the beams), and i have created the slabs but not from the center line of the beams, my idea is how to get the line how the newly created slab is to offset it against the center line of the beam, and how to delete unnecessary slabs (7,8)


please help me, experts, I really appreciate it

210423_Floor from beam(rvt2019).dyn (68.5 KB)