1. A computer-implemented method for deforming a computer displayed three dimensional surface during a continuous input by a user for such deformation, comprising performing the following by computer equipment: displaying, on a computer display, at least one three dimensional geometric surface, which is represented by first data providing a parameterization of the at least one geometric surface, wherein the at least one geometric surface has an at least two dimensional area as a pre-image in the parameterization; accessing respective data representing one or more additional geometric objects used in determining shape modified instances of the at least one geometric surface, each of the one or more additional geometric objects: (i) having a corresponding portion that is coincident with the at least one geometric surface, and (ii) being continuously differentiable; for at least one point of a plurality of user identified points, each of the user identified points included in the corresponding portion coincident with, the at least one geometric surface, receiving a user input for selecting the at least one point, or associated information associated with the at least one point, the associated information providing geometric information characteristic of one of the additional geometric objects having the at least one point; iteratively performing A1 through A4 following so that the user perceives a substantially real time deformation of the at least one geometric surface during a continuous series of user inputs to the computer equipment, wherein each of the user inputs is for entering a corresponding change to one of: a location for the at least one point, or the associated information therefor; (A1) receiving a next one of the user inputs by the computer equipment; (A2) deriving, using the next one of the user inputs received, data representing a modified version of the one additional geometric object, wherein for another point, for the one additional geometric object, the another point being also one of the plurality of user identified points such that the another point is not selected by the user for contributing to the substantially real time deformation, and the another point has second associated data providing a second geometric information characteristic of the one additional geometric object at the another point, then at least one of: (1) the another point, and (2) the second geometric information characteristic remains unchanged and also corresponds with the modified version; (A3) subsequently, determining data representing one of the shape modified instances of the at least one geometric surface, using data representing a modified collection of the one or more additional geometric objects, wherein the modified version of the one additional geometric object is provided in the modified collection; and (A4) displaying the one shape modified instance of the at least one geometric surface on a computer display.