Hierarchical and smoothed topographic path planning for large-scale virtual simulation environments

Virtual simulation systems ought to make the most of agents' realistic behaviors so that users feel immersed in virtual scenarios that mimic the real-world environment. Usually used for training and instruction purposes, agent-based simulations have additional requirements to be considered by the Artificial Intelligence solutions often explored in the development of computer games. To provide a valuable impression of how the simulated agents navigate in the real-world terrain, one of the key requirements indicates that topographic terrain characteristics need to be considered in the path planning tasks. It means that important aspects of the agents' navigation capabilities have to be properly handled by the used pathfinding algorithms. This problem is even more challenging when large-scale terrain scenarios are considered in state-of-the-art simulation systems as the path planning may be too time-consuming when handling terrain representations with large search spaces. To approach the challenge of computing safe and realistic path solutions for agents inserted in simulation-based learning environments, this work discusses a hierarchical pathfinding algorithm named HPATheta*, showing how to compute terrain relief-aware smoothed paths in reasonable computing time when dealing with path planning in large-scale real-world virtual terrains. Using different simulated real-world virtual terrains, the proposal is validated by performing an extensive experimental campaign with the use of large-scale virtual terrain representations. The experimental results indicate that the proposed approach is able to efficiently address the targeted problem, showing better results compared to other similar path planning algorithms.