Before revision:  Virtual and real object occlusions are implemented to enable a natural appearance of virtual bricksinside real bricks . LEGO players' hand detection and occlusion are realized to allow a realistic immersive AR experience, in which virtual bricks can be "grasped" by the real hand, facilitating hand-eye coordination in AR. High accuracy and high precision of registration, i.e. the virtual - physical model alignment, are achieved. In the best case, the average error of registration is less than 1mm throughout the model. BRICKxAR is expected to enhance Learning Through Play, as well as assemblyand construction by human workers. In the experiment, LEGO Arc de Triomphe is built completely with BRICKxAR, without the instruction booklet .
After revision:  Virtual and real object occlusions are implemented to enable a natural appearance of virtual bricksinside real bricks . LEGO players' hand detection and occlusion are realized to allow a realistic immersive AR experience, in which virtual bricks can be "grasped" by real hands. The integration of these features makes AR instructions possible for small-parts assembly, validated through a working AR prototype for constructing LEGO Arc de Triomphe is built completely with BRICKxAR, without the instruction booklet .