Shape of inner disk surface defined as the radial optical depth of τ = 1 (solid line). The model parameters are the same as in Fig. 2. The inner disk radius R_in is marked with the dotted line (the velocity profiles in Fig. 2 follow this line). The dust density scale is set by using the spatial length of 10^-5 AU in the midplane between R_in and τ = 1. The radiation pressure force dominates the region above the dot-dot-dashed line and moves dust particles outward. The disk surface without radiation pressure would extend as far as the dashed line.