1. A method for modifying data representing a geometric object, comprising: displaying, by a computational machine, a first geometric object having a parameterization, wherein the first geometric object has a dimension greater than or equal to two in an object space coordinate system, and wherein the first geometric object has an at least a two dimensional area as a pre-image in a parametric space for the parameterization; wherein for each of the one or more additional geometric objects, respective data therefor is effective for defining a curve where the additional geometric object meets the first geometric object in the object space coordinate system; wherein, for least one of the one or more curves, corresponding marker data is available, the corresponding marker data representing one or more marker points on the at least one curve such that for each of the one or more marker points, there is at least one corresponding marker related extent of one of the additional geometric objects that is used in defining the at least one curve; receiving, by the computational machine, and for the at least one curve, a selection by a user of at least one of the marker points, or the at least one corresponding marker related extent, for the at least one marker point; iteratively performing, by the computational machine, the following steps (A1) through (A4) so that the user is presented with a substantially real time deformation of the first geometric object during a continuous time series of user inputs, wherein each of the user inputs is indicative of a corresponding change to one of: a location for the at least one marker point, or a geometric property of the at least one corresponding marker related extent for the at least one marker point: (A1) receiving a next one of the user inputs; (A2) deriving, using the next one of the user inputs received, data representing a modified version, of the additional geometric object for defining the at least one curve, wherein the modified version is dependent upon the at least one marker point after the change, and, for the ibe additional geometric object, when: (i) another of the marker points of the at least one curve, and (ii) the corresponding marker related extent in the one additional geometric object, and for the another marker point, are each not selected by the user for contributing to the real time deformation than at least one of the another marker points, and the corresponding extent for the another marker point remains unchanged and is also included in the modified version; (A3) subsequently, determining data representing a modified instance of the first geometric object, using data representing a modified collection of the one or more additional geometric objects, wherein the modified version MV of the one additional geometric object is provided in the modified collection, and data for the modified version is used in determining the modified instance, wherein for each pre-image point of a plurality of points of the two dimensional area pre-image, a corresponding substep of combining terms is performed, wherein for each object of the modified collection, one of the terms is determined by computing a product of a weighting, and data representing a particular point of the object, wherein the particular point has the pre-image point as a pre-image, and wherein for each of the pre-image points, the weightings, used in determining the terms for the corresponding substep of combining, satisfy a predetermined constraint; and (A4) displaying the modified instance of the first geometric object to a user.