SHAPE does control the curve of a triggered pitch sweep; using the Flex (Performance) switch, or an Aux switch mapped to it. An expression pedal is unaffected by SHAPE … effectively a linear SHAPE at 0. You can use both at the same time (expression and Flex), with one pitch taking over from the previous one.
Here’s a test preset to demonstrate. Wide intervals between HEEL A & B and TOE A & B. Maximum H-T and T-H GLISS times, to hear the SHAPE develop. 100% wet MIX, and the LP FILTER left at its brightest setting.
There are different ways to describe the SHAPE curves. I’ll skip the scientific or misleading labels. The negative SHAPE values start out slowly, then speed up close to the target [TOE]. That sweep is reversed on release of the Flex switch. The positive values change pitch quickly at first, then slow down towards the end of the sweep.
There are varying degrees of ‘curve’ for fine-tuning, with centered 0 being a straight line between the HEEL and TOE values. That same curve SHAPE can be lengthened or shortened by adjusting the GLISS times.