You can work only in the Top view and only in the range 0 <= x <= 1. Draw a curve in the range like in the picture.
This curve start from point (0,1) to point (1,0). You can see it like a function f(x). The 1-value means an unmodified shape, greater than 1 a bigger shape and smaller than 1 a reduced shape. When the program creates the sweep , it divides the interval from 0 to 1 in as many parts as the times it uses the shape.
To create a deformation graph from this curve use command Edit|Object|Create and choose deformgraph.
A deformation graph can be in any layer, when you create a general sweep you can select it also if in a different layer.
Control
0 Center