On 12/03/2007 08:32 AM, Curtis Olson wrote: > An FDM that uses Motorsport physics could be easily created, but the > interaction between several FDMs is another issue...
Consider the PBY Catalina or other amphibian: -- When it's in the air, it's an aircraft. -- When it's on the water, it's a boat. -- When it's on land, it's a vehicle. I don't recommend it, but these "could" be treated as three separate problems, with three separate dynamics models ... but what we really need is a unified dynamics model that can handle all three cases in a consistent way. Obviously air loads *and* tire loads are important for cars. Ditto for aircraft on the ground. Obviously you need to model the air *and* the water for sailboats. And while an amphibian is crawling out of the water onto land, it is in all three worlds at once. I don't much care what you call it. -- On this list heretofore, it has usually been called the flight dynamics model (FDM). -- In the world of boats, it is called the fluid dynamics model (again FDM). -- As soon as we have tires on pavement, those names are no longer apt. -- You can also have a structural dynamics model. Alternatives include plain old Dynamics Model (DM or DyMo) or of course Physics Engine (PhEng). Beware that there is a huge legacy here; there are nearly ten thousand mentions of the term "FDM" in the flightgear file tree, so even though the term isn't apt, it is going to remain with us for quite a while. In the interests of backward compatibility, it might be simplest to declare that FDM stands for Fine Dynamics Model (as in RTFM == "Read the Fine Manual"), and declare that the ideal FDM should include air, water, tires, and mechanical interactions. Going forward, "Physics Engine' is as good a name as any, and is consistent with usage in the rest of the modeling community. ------------------------------------------------------------------------- SF.Net email is sponsored by: The Future of Linux Business White Paper from Novell. From the desktop to the data center, Linux is going mainstream. Let it simplify your IT future. http://altfarm.mediaplex.com/ad/ck/8857-50307-18918-4 _______________________________________________ Flightgear-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/flightgear-devel
