It might be worthwhile looking into how games like ME3 accomplish their MP bullet physics.


AFAIK, drawing a low-poly arc in the game whenever a bullet is fired should be workable, because then all the server needs to do is 'update' the 'bullet position' along that arc every milisecond or so, and check to see if any players are in contact with the 'bullet'.  Animations would be entirely client-side.  Instead of a true CPU-intensive bullet, a reasonably simple physics-analogue formula can be used to simulate a bullet, and fairly accurately at that.

The only considerations in the formula would need to be:

 - Aiming angle
 - Bullet 'velocity'
 - Map gravity
 - Windage (probably not in Trem)
 - Deceleration (shotgun pellets)

the server needs to do is 'update' the 'bullet position'

What is really sent between server and clients? Only the xyz coordinates of stuff that can move in-game?

Bullet penetration would be nice. So if a tyrant has really tough armor, weapon damage is greatly reduced if the weapon doesn't have good penetration. Projectile weapons would suffer little reduction from penetration, while energy weapons and weapons that have a splash damage effect will do little damage.

The downside to projectile weapons would be that they suffer great damage reduction the longer they travel and have a parabolic trajectory, while energy weapons are uneffected.

Projectile Weapons:
rifle
shotgun
chaingun

Energy Weapons:
blaster
lasgun
pulse rifle
mass driver
lucifer cannon

Splash Damage Weapons:
grenades
flame thrower
lucifer cannon

- Windage (probably not in Trem)

Wrong. Check F server from the XserverX/blogwtf section of tremulous 1.1. You're a 1.1 player, so unless you haven't been there recently, you should already know this.

The downside to projectile weapons would be that they suffer great damage reduction the longer they travel and have a parabolic trajectory, while energy weapons are uneffected.

Realistic wise, energy is loss as light is emitted. The only way to 100% conserve energy is by making it 100% invisable, uneffected by air particles (hence makes it uneffected by the body of the aliens) hence makes the whole thing useless.
But everyone knows we want gameplay, not realism.

Projectile weapons would suffer little reduction from penetration, while energy weapons and weapons that have a splash damage effect will do little damage.

I wouldn't say so.
Aluminium as thin as a can can be penetrated easily by bullets, however if you increase that thickness by two or so centimetres, almost no standard machinegun can penetrate that.
Considering the size of the tyrant's belly plate, that must be about 10-20 or so centimeters thick of thick organic flexable armour (there's also the potential idea of the armour being sticky in the inside, further slowing the bullet down), i doubt the bullet would reach the tyrant's organs from the front.

Realistic wise, energy is loss as light is emitted. The only way to 100% conserve energy is by making it 100% invisable, uneffected by air particles (hence makes it uneffected by the body of the aliens) hence makes the whole thing useless.
But everyone knows we want gameplay, not realism.

Virus.

Physics-analog algorithm, not super computational simulation.

Also, I never said 1.1 was using windage physics (it obviously doesn't), only that T2 may want to include it because of the large outdoor maps.