A method for modifying a seam curve in a computer-aided design model to attain the location and shape of a new seam curve and to maintain seam network connectivity, the method performed by a data processing system and comprising: a) receiving at least one input through a user interface 1318 to modify a curve or a seam, where at least input is selected from group comprising type of curve to implemented as a new curve, location of one or more offset points, maximum offset space, location of one or more limit points of a transition curve and fullness value to be implemented when forming the new curve; b) identifying an original curve and an intended location of the new curve in the CAD model, the identifying including the identifying of at least two limit points (306, 308) to define the limits or ends of original curve where a modification can occur and one offset point along the original curve (202, 302) and determines the point from which the original curve 302 can be moved in order to transition from the location of the original curve 302 to the location of the new curve 304; c) generating a transition curve from the original curve by the offset point moving the original curve to the position of the new curve such that at least one offset point of the transition curve intersects along the location of the new curve; d) determining a displacement function of the new curve based on fullness value and applying the displacement function to the transition curve such that the transition curve (312B, 312A) overlays the new curve in the same position and with the same shape, wherein the displacement function includes two or more controls (354, 356; 374, 376) which controls controlling movement of an associated point (384, 386) so as to shape the transition curve (312A, 312B) into the shape of the new curve; e) combining the two or more controls (354, 356; 374, 376) into one transition curve control such that movement of the associated points (384, 386) is locked in unison; f) adjusting the transition curve control based on a fullness value so that the transition curve overlays the location of the new curve, wherein the fullness value is a horizontal distance in a Cartesian coordinate graph between a midpoint of a line along the displacement function and another point (382, 388) in the Cartesian coordinate graph; and g) modifying one or more connecting curves (204, 206, 208, 210) which terminate at one or more points along the original curve so that the one or more connecting curves (204, 206, 208, 210) terminate at one or more points along transition curve. a) receiving at least one input through a user interface 1318 to modify a curve or a seam, where at least input is selected from group comprising type of curve to implemented as a new curve, location of one or more offset points, maximum offset space, location of one or more limit points of a transition curve and fullness value to be implemented when forming the new curve; b) identifying an original curve and an intended location of the new curve in the CAD model, the identifying including the identifying of at least two limit points (306, 308) to define the limits or ends of original curve where a modification can occur and one offset point along the original curve (202, 302) and determines the point from which the original curve 302 can be moved in order to transition from the location of the original curve 302 to the location of the new curve 304; c) generating a transition curve from the original curve by the offset point moving the original curve to the position of the new curve such that at least one offset point of the transition curve intersects along the location of the new curve; d) determining a displacement function of the new curve based on fullness value and applying the displacement function to the transition curve such that the transition curve (312B, 312A) overlays the new curve in the same position and with the same shape, wherein the displacement function includes two or more controls (354, 356; 374, 376) which controls controlling movement of an associated point (384, 386) so as to shape the transition curve (312A, 312B) into the shape of the new curve; e) combining the two or more controls (354, 356; 374, 376) into one transition curve control such that movement of the associated points (384, 386) is locked in unison; f) adjusting the transition curve control based on a fullness value so that the transition curve overlays the location of the new curve, wherein the fullness value is a horizontal distance in a Cartesian coordinate graph between a midpoint of a line along the displacement function and another point (382, 388) in the Cartesian coordinate graph; and g) modifying one or more connecting curves (204, 206, 208, 210) which terminate at one or more points along the original curve so that the one or more connecting curves (204, 206, 208, 210) terminate at one or more points along transition curve.