1. A method for using curves to emulate soft body deformation in computer animation, the method comprising: accessing a reference model mapped to a deformation curve for a computer-generated character, the reference model including a mesh of vertices representing a soft body layer of the character and the deformation curve including a plurality of sample points, wherein each vertex of the model is mapped to each point of the curve; receiving a movement of at least one point on the curve; calculating a normal vector to the at least one point on the curve; calculating an offset between positions of the at least one point on the curve prior to and after the movement of the at least one point; calculating primary movements of the vertices of the model based on the calculated offset of the at least one point on the curve, wherein the primary movements are along a vector direction of the movement of the at least one point on the curve, and wherein the primary movements represent deformation of the reference model from a reference state to a deformed state; calculating secondary movements of the vertices of the model based on the calculated offset of the at least one point on the curve, wherein the secondary movement of a vertex is along a vector direction perpendicular to the normal vector and in a plane formed by the normal vector, the vertex's position, and the position of the at least one point on the curve prior to movement, and wherein the secondary movements represent subsequent deformation emulating soft body volume preservation as a result of the primary movements; moving the vertices of the model according to the calculated primary and secondary movements; and outputting the model with the moved vertices for rendering to emulate the soft body deformation of the character.