The sliders associated with this tab add curvature to parallels. Dragging to the right (positive values) bows parallels away the equator for a convex effect. Dragging to the left (negative values) bows parallels toward the equator for a concave effect. The default value of 0 indicates straight parallels. With bending, users can create projections with polyconic-like properties.

The Curve pop-up menu at the bottom of the Flex Projection panel offers different formulas for bending parallels. The choices are cubic, quadratic, and cosine.

Selecting Remove Bending Adjustments in the Options popup menu resets parallels to straight lines.