1. A method of computer-aided design of a 3D object modeled by: (i) cells, the cells being restrictions of geometries of a model of the 3D object, and (ii) a cell graph comprising relations between the cells, which relations capture a topology of the model, the method comprising the steps of: editing an initial model by interacting with a user to identify intended displacements of initial geometries of the model, and selecting the cells which are restrictions of the geometries to be displaced; collecting cells adjacent to the selected cells according to the cell graph, some of the adjacent cells being excluded by predefined rules, wherein said predefined rules comprise at least one of sets of rules among (a) a set of rules limiting adjacency to a nth-order adjacent cell in the cell graph, and (b) a set of rules excluding, from said adjacent cells to be collected, any cell corresponding to a regular vertex bounding a collected cell; computing by a solver, transformations to be applied to initial geometries, from the intended displacements and geometries whose collected cells are restrictions thereof; and building new geometries according to said transformations and initial geometries.