Shape modeling research in Computer Graphics has been an active area for decades. The ability to create and edit complex 3D shapes has been of key importance in Computer-Aided Design, Animation, Architecture, and Entertainment. With the growing popularity of Virtual and Augmented Reality, new applications and tools have been developed for artistic content creation; real-time interactive shape modeling has become increasingly important for a continuum of virtual and augmented reality environments (eXtended Reality (XR)). Shape modeling in XR opens new possibilities for intuitive design and shape modeling in an accessible way. Artificial Intelligence (AI) approaches generating shape information from text prompts are set to change how artists create and edit 3D models. There has been a substantial body of research on interactive 3D shape modeling. However, there is no recent extensive review of the existing techniques and what AI shape generation means for shape modeling in interactive XR environments. In this state-of-the-art paper, we fill this research gap in the literature by surveying free-form shape modeling work in XR, with a focus on sculpting and 3D sketching, the most intuitive forms of free-form shape modeling. We classify and discuss these works across five dimensions: contribution of the articles, domain setting, interaction tool, auto-completion, and collaborative designing. The paper concludes by discussing the disconnect between interactive 3D sculpting and sketching and how this will likely evolve with the prevalence of AI shape-generation tools in the future.

翻译：计算机图形学中的形状建模研究数十年来一直是活跃领域。创建和编辑复杂三维形状的能力在计算机辅助设计、动画、建筑和娱乐领域具有关键意义。随着虚拟现实和增强现实的日益普及，面向艺术内容创作的新应用与工具不断涌现；实时交互式形状建模在虚拟现实与增强现实环境（扩展现实（XR））的连续统中变得愈发重要。XR中的形状建模为直观设计与形状建模开辟了新的可能性。基于文本提示生成形状信息的人工智能（AI）方法将重塑艺术家创建和编辑三维模型的方式。尽管已有大量关于交互式三维形状建模的研究，但当前仍缺乏对现有技术及AI形状生成在交互式XR环境中形状建模意义的系统性综述。本文作为最新技术综述，通过梳理XR中的自由形态形状建模工作（重点关注最直观的自由形态建模形式——雕刻与三维草图），填补了这一研究空白。我们从五个维度对这些工作进行分类与讨论：文章贡献、领域设定、交互工具、自动补全和协同设计。论文最后探讨了交互式三维雕刻与草图之间的脱节现象，以及随着未来AI形状生成工具的普及，这种脱节将如何演变。