Interior 8 1/2" rounded paneling milled from the same kiln dried pine we use for our laminated logs given the warmth and comfort of a log cabin to this dry-walled room. Rough sawn beams have added to the ambiance.
Corner detail is a matter of personal preference, and adds character to any installation. In this case, the homeowner has elected to use log cabin chinking in the corners. One option would be to use a piece of vertical corner trim. Another would be to butt one piece of paneling to the other by cutting a half moon in one piece.