Screen-space Streamline Seeding Method for Visualizing Unsteady Flow in Augmented Reality

Streamlines are a popular method of choice in many flow visualization techniques due to their simplicity and intuitiveness. This paper presents a novel streamline seeding method, which is tailored for visualizing unsteady flow in augmented reality (AR). Our method prioritizes visualizing the visible part of the flow field to enhance the flow representation's quality and reduce the computational cost. Being an image-based method, it evenly samples 2D seeds from the screen space. Then, a ray is fired toward each 2D seed, and the on-the-ray point, which has the largest entropy, is selected. It is taken as the 3D seed for a streamline. By advecting such 3D seeds in the velocity field, which is continuously updated in real time, the unsteady flow is visualized more naturally, and the temporal coherence is achieved with no extra efforts. Our method is tested using an AR application for visualizing airflow from a virtual air conditioner. Comparison with the baseline methods shows that our method is suitable for visualizing unsteady flow in AR.