Products fabricated by metal casting are affected by casting design and pouring. In order to design products efficiently, engineers must consider the shape of the pouring gate and the fluidity of metal in the runner. Engineers must envision the shape of the product and the fluidity of the metal in three dimensions. However, this task is difficult, especially for beginners. Therefore, we developed an augmented reality-based training system for metal casting that allows visualization of fluidity. The proposed training system uses simple physical operations to compute and display fluidity in real-time. Visualization of three-dimensional images as well as training on this system is simple.