增材制造（AM）在设计和工程中的融合促使了广泛的研究工作，涉及拓扑优化的固体/晶格结构、多材料结构、仿生有机结构和多尺度结构等。然而，除了明显的情况，很少有人关注更复杂的三维（3D）空心结构或折叠/褶皱结构的设计和打印。主要原因之一是，这种复杂的开放或封闭的3D空腔和规则/自由形态的褶皱通常会带来与支撑结构相关的打印难题。为了解决这一障碍，本文旨在研究四维（4D）打印以及基于折纸的设计，作为设计和建造3D无支撑空心结构的原创研究方向。本研究包括用没有任何支撑结构的二维（2D）打印折纸前体布局来描述粗糙的3D空心结构。然后，这种基于折纸的定义体现了折叠功能，可以由3D打印的智能材料来驱动和实现。一旦对活性材料施加外部刺激，所需的3D形状就会被建立起来，从而确保2D折纸布局向3D结构的转变。为了证明该方案的实用性，本文介绍了一些说明性的案例。

The integration of additive manufacturing (AM) in design and engineering has prompted a wide spectrum of research efforts, involving topologically optimized solid/lattice structures, multimaterial structures, bioinspired organic structures, and multiscale structures, to name a few. However, except for obvious cases, very little attention has been given to the design and printing of more complex three-dimensional (3D) hollow structures or folded/creased structures. One of the main reasons is that such complex open or closed 3D cavities and regular/freeform folds generally lead to printing difficulties from support-structure-related issues. To address this barrier, this paper aims to investigate four-dimensional (4D) printing as well as origami-based design as an original research direction to design and build 3D support-free hollow structures. This work consists of describing the rough 3D hollow structures in terms of two-dimensional (2D) printed origami precursor layouts without any support structure. Such origami-based definitions are then embodied with folding functions that can be actuated and fulfilled by 3D printed smart materials. The desired 3D shape is then built once an external stimulus is applied to the active materials, therefore ensuring the transformation of the 2D origami layout to 3D structures. To demonstrate the relevance of the proposal, some illustrative cases are introduced.