Rotary cutters are tools with circular blades that can be continuously pushed or pulled to make cuts into fabrics, leathers, and many materials. Since the blades rotate, they can cut along curves very easily, making them a great option for more complex designs.
Rotary cutters also cut straight lines very well, usually when used with a straight edge as a guide. Blades are as sharp as other knife-style blades and can be sharpened often and replaced when necessary. This is a great tool when looking for something beyond a fixed blade knife.