Figure 1.

Schematic representation of our vertex models. (A and B) Schematic representation of the 3D model. (A) A model 3D cell with distinct apical, basal, and lateral surfaces. (B) Schematic highlighting different tension terms in the 3D vertex model. (C) Schematic explanation of the modified 2D vertex model. The modified 2D model idealizes the epithelial sheet as the midsurface (shown in black) of an epithelial monolayer with finite thickness 2h and assumes that a contractile segment (shown in gray) joins the centers of the apical faces. (D) The figure shows two adjacent 2D cells S1 and S2 with shared edge j, cell centers (C_S1, C_S2), and unit outward normals (N_S1, N_S2), pointing toward the outer shell. The value ${\mathit{u}}_{j^{\prime }}$ is the unit vector joining the cell centers and h is the offset parameter. See text for more details. The red line highlights a contractile segment that is offset by a distance from the surface along the cell normals. To see this figure in color, go online.