A computer implemented method for modification of a generative design, the method comprising: modifying, by a computer aided design program, a three dimensional shape of a modeled object, for which a corresponding physical structure is to be created using an additive manufacturing process, to produce a modified three dimensional shape of the modeled object, wherein the modifying comprises, for each of two or more discrete layers of the three dimensional shape along a build direction of the additive manufacturing process extracting a two dimensional profile representation of the three dimensional shape in a current discrete layer, the two dimensional profile representation lying in a plane that is perpendicular to the build direction associated with the additive manufacturing process, offsetting the two dimensional profile representation by an amount associated with the additive manufacturing process to form an offset two dimensional profile representation of the current discrete layer, wherein the offsetting comprises offsetting the two dimensional profile representation inward by the amount, which is determined in accordance with a maximum overhang angle for the additive manufacturing process, and changing a next discrete layer along a negative build direction, which is reverse to the build direction, using the offset two dimensional profile representation of the current discrete layer; and providing, by the computer aided design program, the modified three dimensional shape of the modeled object for use in manufacturing the physical structure using one or more computer-controlled manufacturing systems that employ the additive manufacturing process, wherein the providing comprises generating toolpath specifications for an additive manufacturing machine using the designed three dimensional shape of the modeled object for manufacturing at least a portion of the physical structure with the additive manufacturing machine using the toolpath specifications. modifying, by a computer aided design program, a three dimensional shape of a modeled object, for which a corresponding physical structure is to be created using an additive manufacturing process, to produce a modified three dimensional shape of the modeled object, wherein the modifying comprises, for each of two or more discrete layers of the three dimensional shape along a build direction of the additive manufacturing process extracting a two dimensional profile representation of the three dimensional shape in a current discrete layer, the two dimensional profile representation lying in a plane that is perpendicular to the build direction associated with the additive manufacturing process, offsetting the two dimensional profile representation by an amount associated with the additive manufacturing process to form an offset two dimensional profile representation of the current discrete layer, wherein the offsetting comprises offsetting the two dimensional profile representation inward by the amount, which is determined in accordance with a maximum overhang angle for the additive manufacturing process, and changing a next discrete layer along a negative build direction, which is reverse to the build direction, using the offset two dimensional profile representation of the current discrete layer; and extracting a two dimensional profile representation of the three dimensional shape in a current discrete layer, the two dimensional profile representation lying in a plane that is perpendicular to the build direction associated with the additive manufacturing process, offsetting the two dimensional profile representation by an amount associated with the additive manufacturing process to form an offset two dimensional profile representation of the current discrete layer, wherein the offsetting comprises offsetting the two dimensional profile representation inward by the amount, which is determined in accordance with a maximum overhang angle for the additive manufacturing process, and changing a next discrete layer along a negative build direction, which is reverse to the build direction, using the offset two dimensional profile representation of the current discrete layer; and providing, by the computer aided design program, the modified three dimensional shape of the modeled object for use in manufacturing the physical structure using one or more computer-controlled manufacturing systems that employ the additive manufacturing process, wherein the providing comprises generating toolpath specifications for an additive manufacturing machine using the designed three dimensional shape of the modeled object for manufacturing at least a portion of the physical structure with the additive manufacturing machine using the toolpath specifications.