Topology optimization of structure with multiple targets

Methods, systems, and apparatus, including medium-encoded computer program products, for computer aided design of physical structures, which can be built using various manufacturing systems and techniques, include, in one aspect, a method including: obtaining a design space for a modeled object, design criteria, an in-use load case, one or more materials specifications, and one or more safety factors; producing at least one generatively designed 3D topology of the modeled object, including, starting from an initial design, generating a first design in accordance with a first target defined by a first of the specifications or of the safety factors, and starting from the first design or an intermediate design generated between the initial design and the first design, generating a second design in accordance with a second target defined by a second of the specifications or of the safety factors; and providing both the first design and the second design.