Argorha Pathfinding is an algorithm which permit you to find your way into a polygon soup ( 3D world ) efficently by precalculating a system of sectors and portals. AStar included.
This is the code I did for an unfinished game back in 2006. It is not maintained anymore. I'm putting it on GitHub for demo purpose only.
Use Recast navigation instead which is way better than this solution. https://github.com/memononen/recastnavigation