Topology optimization is a mathematical method to optimally distribute materials within a given design domain subject to the physical boundary conditions [
1]. Its key advantage is in exploring a larger design space (compared to size and shape optimization) with faster convergence (compared to global optimization). The past few years have witnessed the rapid expansion of topology optimization in covering increasingly more multidisciplinary structural design problems [
2,
3]. On the other hand, even though designers have greatly enjoyed the creative design power of topology optimization, manufacturing engineers often take issues with the organic shapes produced by topology optimization being difficult or even impossible to manufacture, even though many efforts have been put into this aspect [
4]. These days, additive manufacturing (AM) technology emerges and has partially relieved many of the manufacturability issues since the layer-by-layer material deposition process of AM makes manufacturing of any complex geometry much cheaper and faster [
5]. Hence, topology optimization for AM has recently become very popular and has attracted attention from both academia and industry. Many tough topology optimization for AM issues have been addressed including self-support design to eliminate need of the costly support structure [
6–
11], material anisotropy issue to address the tool path or build direction-induced anisotropic material properties [
12–
16], multi-scale design to explore the extreme design space enabled by AM [
17–
21], and many others [
22]. These achievements lead to a better marriage between topology optimization and AM.