[barrettcolin]

I'm not sure where I picked up the info, and I haven't looked at the code to confirm it, but I believe the physics engine implementation is tied tightly to both the collision detection system and the entity update, both of which are quite specific to Doom (in particular, each entity steps physics independently, rather than a whole simulation advancing at once as is common in 'pluggable' physics engines like ODE, Havok etc).

Also, and this is subjective I suppose, I don't remember Doom 3 doing anything that 'felt' or looked better than even what the contemporaneous engines did (such as the version of Havok used in Half-Life 2).

So I guess, there probably aren't valuable additions, but I imagine there is much to tinker with.

[barrettcolin]

For the sake of completeness, here is where I read that: http://www.ode.org/old_list_archives/2004-December/014735.ht...

From looking at the game code, I see odd things like rolling barrels animating their rotation as though the physics engine itself doesn't handle rolling contact.