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、原位3D增强现实（AR）指令方法及其在小型零件装配中的应用——BRICKxAR（多3D模型/M3D）。BRICKxAR（M3D）能在物理装配模型的装配位置真实感地呈现渲染后的3D装配零件（图1）。用户通过用户界面控制装配过程。BRICKxAR（M3D）采用基于深度学习训练的3D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，装配过程中相机未必能捕捉到3D装配体中的所有零件。BRICKxAR（M3D）通过将多个装配阶段与步骤计数相结合来解决这些难题。因此，使用较少的阶段可简化复杂装配流程，而步骤计数则有助于实现每个步骤的精确目标识别和精准可视化。我们通过与用户及可视化与人机交互领域专家进行的BRICKxAR（M3D）原型测试与启发式评估及定性分析，验证了该方法。通过提供鲁棒的3D AR指令并允许操作装配模型，BRICKxAR（M3D）有望应用于从制造装配到建筑施工的不同尺度场景。