Luminosity constant models of axisymmetric circumstellar dust shells are calculated. The models consist of either donut-like or disklike distributions of silicate grains surrounding a 3000 K star. An iterative scheme is used to solve the radiative transfer problem taking into account both scattered and thermal radiation. Maps for models with varying degrees of asymmetry and optical thickness of the shell and for various inclinations of the line of sight to the axis of symmetry are presented. One-dimensional visibility amplitudes and angular sizes are computed for scans of the maps in two perpendicular directions. It is shown that one-dimensional visibility measurements at 10 and 20 microns may be used to distinguish between the two types of dust density distributions considered here. 30 refs.