A system for modifying a design file of an object for additive manufacturing, comprising: a computer control system comprising one or more computers (102a, 102b, 102c, 102d) having a memory and a processor, the computer control system configured to: determine if one or more surfaces of the object have a surface angle below a threshold angle, wherein the surface angle is calculated as the angle between the normal from the plane of the surface, and the normal from the build surface the object is to be built on and wherein the threshold angle is a minimum surface angle for the surface to be self-supporting; wherein the computer control system is further configured to modify the design file of the object by: adding one or more connecting lines (610, 615) including a first line, the first line being between a first surface of the one or more surfaces and a second surface of the one or more surfaces, wherein the first surface has a surface angle below the threshold angle and the second surface has a surface angle equal to or above the threshold angle; generating one or more additional surfaces (612, 615) along the one or more connecting lines in the design file, and characterized in that the computer control system is further configured to modify the design file of the object by: modifying a wall thickness of each surface of the object with a thickness below a minimum threshold for the object to be self-supporting to a thickness that is at or above the minimum thickness threshold. determine if one or more surfaces of the object have a surface angle below a threshold angle, wherein the surface angle is calculated as the angle between the normal from the plane of the surface, and the normal from the build surface the object is to be built on and wherein the threshold angle is a minimum surface angle for the surface to be self-supporting; wherein the computer control system is further configured to modify the design file of the object by: adding one or more connecting lines (610, 615) including a first line, the first line being between a first surface of the one or more surfaces and a second surface of the one or more surfaces, wherein the first surface has a surface angle below the threshold angle and the second surface has a surface angle equal to or above the threshold angle; generating one or more additional surfaces (612, 615) along the one or more connecting lines in the design file, and characterized in that the computer control system is further configured to modify the design file of the object by: modifying a wall thickness of each surface of the object with a thickness below a minimum threshold for the object to be self-supporting to a thickness that is at or above the minimum thickness threshold. adding one or more connecting lines (610, 615) including a first line, the first line being between a first surface of the one or more surfaces and a second surface of the one or more surfaces, wherein the first surface has a surface angle below the threshold angle and the second surface has a surface angle equal to or above the threshold angle; generating one or more additional surfaces (612, 615) along the one or more connecting lines in the design file, and characterized in that the computer control system is further configured to modify the design file of the object by: modifying a wall thickness of each surface of the object with a thickness below a minimum threshold for the object to be self-supporting to a thickness that is at or above the minimum thickness threshold.