In this paper, the novel design mode of human-aided design (HAD) is proposed to replace conventional
computer-aided design (CAD). In HAD, computers can automatically complete the whole product design
via a new isogeometric topology optimization (ITO), while humans just assist to slightly modify the
design to meet requirements. An embedded domain ITO is presented to design complex models with
irregular design domains, and editable geometric models of optimized results can be automatically generated
based on layered ITO results. Three examples are tested to verify the proposed HAD mode, including
a 3D cantilever beam with a regular design domain, an automotive part with an irregular design
domain, and a Messerschmitt-Bölkow-Blohm (MBB) beam with a multiscale structure. The results
demonstrate that the proposed HAD mode can automatically deliver high-quality optimized models;
thus, it has great potential as a revolutionary technology to change the current design mode from CAD
to HAD.