Designers often use wood posts, cross beams, and rafters to lend interiors a traditional, or even rustic, feel. These elements can also more subtly influence room design.

Because of their visual heft, wood beams can alter one's perception of space. Exposed rafters, cross beams, and timbers can "help bring the scale down and add a more human dimension," says Michael Klement of Architectural Resources, Ann Arbor, Mich. Posts and cross beams in particular, he says, can create a more intimate feel in spacious or high-ceilinged rooms by bringing the ceiling closer to the floor plane or drawing walls closer together.

"When you're in a big open space, you feel kind of lost," says Nancy McCarren of Muse Architects, Washington, D.C. "It helps a design to add elements of a scale people can relate to."