A nonrigid transformation describes any transformation of a geometrical object that changes the size, but not the shape. Stretching or dilating are examples of non-rigid types of transformation.
A transformation describes any operation that is performed on a shape. Simple transformations, such as moving the object to the left, do not change the size or shape of the object. These types of transformations are known as rigid transformations. Another common type of transformation is a reflection, where the object is flipped to reveal its mirror image, which is another rigid transformation. The final type of rigid transformation is rotation, where the object is rotated in either direction.