Perspective with Multiple Buildings

Using perspective with a common horizon line allows the two barns to sit together on the same plane.  They will look like they belong together in the scene. 

There will only be one horizon line (eye level). All the buildings will meet at the same 2 convergence "X's" on the horizon line.

The green line is the horizon line. The red lines are for the foreground building. The blue lines are for the building in the background.