Off-road path planning based on TIN with cross-node connection

In path planning for 3D off-road environments, efficiently generating paths that satisfy relative slope constraints has long been a persistent challenge. Traditional algorithms, restricted by the limited adjacent directions in Regular Grids (DEM) or Triangulated Irregular Networks (TIN), not only struggle to produce slope-compliant paths in steep terrain but also frequently result in low-quality paths due to data redundancy or unnecessary detours. To address this issue, this study proposes a cross-node connection method based on contour-constrained TIN: First, a Relax-Slope strategy is designed, leveraging the geometric properties of contour-constrained TIN to construct relaxation sequences across contour nodes, enabling rapid identification of cross-node paths that meet relative slope thresholds. Simultaneously, an enhanced TIN network structure is built to explicitly store contour association information, supporting efficient computations. On this basis, the RS-A* embedded improved algorithm is proposed to realize cross-node path planning on TIN. Experimental verification shows that the proposed algorithm significantly outperforms traditional algorithms in path length and planning efficiency under relative slope constraints, indicating that this research effectively breaks through direction limitations and efficiency bottlenecks, and can plan off-road paths more aligned with real maneuver characteristics, thus providing a reliable path planning solution for scenarios such as military operations and emergency responses in complex terrain.