Confined equilibrium quantum gases are mor complicated than standard theory suggests. Blackbody radiation and other quantum gases in free space are uniform everywhere. However when confined by a boundary to some region of space they become nonuniform---a function of position with respect to the boundary. Standard theory based on the heat kernal expansion distorts boundary effects into distributions defined on the boundary. Here an exact, local description of boundary effects is presented for scalar gases confined by a general boundary. Explicit calculations for boundaries with a rectangular geometry illustrate all major points.