These options appear as a subset of the section in the Paint Effects Brush Settings window, and the Attribute Editor for any brush node.
Bend can be used to curl up leaves and flowers, as well as to make the overall branches bend in the U direction (along the length). You can create natural looking flower petals and plants, such as fiddle head ferns. It is automatically animated in growth animations if non-zero. You can use the Curl attribute to bend leaves and petals in the V direction (along the width).
Defines how much bend is applied to base tubes. Bend can be used to curl up leaves and flowers, as well as to make the overall branches bend in the U direction (along the length). See also Leaf Bend and Petal Bend.
Controls how far down the stroke the bend starts. With a value of 0, the bend starts at the base. With a value of 1, there is no bend. High values cause a faster bending near the tip.