A 3D RTS I worked on in the mid 90's used A* in a couple of ways to do pathfinding.
1. First generation was to use a series of 'way points' that was created with the landscape/level generator itself. They were the basic 'paths of best flow' in a very broad sense. It was used when a player sent troops from one side of the map to the other. There was only 20-40 of these on a map.
2. Second generation used a much finer granularity that was a lookup of preprocessed surface normals on the terrain.
So, the tank/unit would look at the waypoints to know generally which way is the 'best ish' way, and use a finer grained one for the first and last mile.
We also used collision avoidance schemes so you could pass one group of vehicles 'thru' another and they'd miss one another in a logical way (ie small deviations left/right based upon own vs. other speed).
We ended up not using the 'one vehicle per square' technique that may RTS used at the time -- we didn't need to.
1. First generation was to use a series of 'way points' that was created with the landscape/level generator itself. They were the basic 'paths of best flow' in a very broad sense. It was used when a player sent troops from one side of the map to the other. There was only 20-40 of these on a map.
2. Second generation used a much finer granularity that was a lookup of preprocessed surface normals on the terrain.
So, the tank/unit would look at the waypoints to know generally which way is the 'best ish' way, and use a finer grained one for the first and last mile.
We also used collision avoidance schemes so you could pass one group of vehicles 'thru' another and they'd miss one another in a logical way (ie small deviations left/right based upon own vs. other speed).
We ended up not using the 'one vehicle per square' technique that may RTS used at the time -- we didn't need to.