Hi Polar Bear,
This is probably because you are using the same building material for both objects I think. If you need them to show a line then and want to use the same material you can duplicate the material and name it differently say "Wood-1" and the other one "Wood-2". Then set the beams to have the other material name.
"The simplification of anything is always sensational" GKC
AC 25-4013 USA, CadImage Tools
2019 MacBook Pro 16" w/ AMD Radeon Pro 5600M GPU
OS X 11.6
2.4 Ghz 8 core i9, 64 GB RAM
27" LG 5K Monitor