This paper introduces a novel, markerless, step-by-step, in-situ 3D Augmented Reality (AR) instruction method and its application - BRICKxAR (Multi 3D Models/M3D) - for small parts assembly. BRICKxAR (M3D) realistically visualizes rendered 3D assembly parts at the assembly location of the physical assembly model (Figure 1). The user controls the assembly process through a user interface. BRICKxAR (M3D) utilizes deep learning-trained 3D model-based registration. Object recognition and tracking become challenging as the assembly model updates at each step. Additionally, not every part in a 3D assembly may be visible to the camera during the assembly. BRICKxAR (M3D) combines multiple assembly phases with a step count to address these challenges. Thus, using fewer phases simplifies the complex assembly process while step count facilitates accurate object recognition and precise visualization of each step. A testing and heuristic evaluation of the BRICKxAR (M3D) prototype and qualitative analysis were conducted with users and experts in visualization and human-computer interaction. Providing robust 3D AR instructions and allowing the handling of the assembly model, BRICKxAR (M3D) has the potential to be used at different scales ranging from manufacturing assembly to construction.

翻译：本文提出了一种新颖的无标记、逐步式、原位三维增强现实（AR）指令方法及其应用——BRICKxAR（多三维模型/M3D），用于小型零件装配。BRICKxAR（M3D）在物理装配模型的装配位置处真实可视化渲染的三维装配零件（图1）。用户通过用户界面控制装配过程。BRICKxAR（M3D）利用基于深度学习训练的三维模型配准技术。由于装配模型在每一步都会更新，目标识别与跟踪面临挑战。此外，三维装配体中的部分零件在装配过程中可能无法被摄像头捕捉。BRICKxAR（M3D）通过将多个装配阶段与步骤计数相结合来应对这些挑战。因此，使用较少的阶段可简化复杂的装配过程，而步骤计数则有助于实现每个步骤的精准目标识别与精确可视化。我们与用户及可视化与人机交互领域的专家共同开展了BRICKxAR（M3D）原型的测试与启发式评估及定性分析。通过提供鲁棒的三维AR指令并允许对装配模型进行操作，BRICKxAR（M3D）具有从制造装配到建筑工程等不同尺度场景的应用潜力。