object.dat

The object.dat file is located in the /data directory of GTA III, Vice City, and San Andreas, or the /common/data directory of GTA IV. It defines the physical aspects of objects defined in IDE files.

Format

		Name in file	Data type	Description
A		Object name	string	Object name. Maximum of 256 characters in length.
B		Mass	float	1 to 50000 inclusive. Unit is kilograms.
C		TurnMass	float	The description within the file says kg m^3 or some such dimension, but kg/m3 is actually the unit of density. However, kg/m2 is the unit of rotational inertia, which is sometimes referred to as "rotational mass" (and could be what "TurnMass" is referring to).
D		Air Resistance	float	Normalised between 1 and 0. 0 means complete air resistance, 1 means no air resistance. Most objects have a value of 0.99 for this attribute.
E		Elasticity	float	How much the object bounces when it collides with something. Normalised. 0 is the least bouncy, 1 is the most.
F		Percent Submerged	float	10 to 120. Most objects have a value of 50.0 for this attribute.
G		Uproot Force	float	The magnitude of the force vector that must be applied to the object to remove it from the ground. Possibly Newtons, but no units given.
H		Collision Damage Multiplier	float	Controls how much damage a collision with this object should do to vehicles. "0.1 - 5.0 ish" according to the file.
I		Collision Damage Effect	integer	What happens to the object when it is collided with. Values: 0 = Nothing 1 = Changes model 20 = Smashes 21 = Changes model and then smashes 200 = Breaks 202 = Breaks and does not get regenerated when the area is reloaded
J		Special Collision Response Cases	integer	Specifies if the game has a custom response for collisions with this object, and what the response should be if there is one. Values: 0 = Normal (no custom response) 1 = Lamp post 2 = Small box 3 = Big box (unused in the file) 4 = Fence section 5 = Grenade (unused in the file) 6 = Swinging door 7 = Locked door 8 = Hanging (like the punchbag in the gym) 9 = Pool ball
K		Camera to avoid this object	integer	Boolean (written as 1 or 0, not true/false) that controls whether the camera should move around the object.
	L	Causes Explosion	integer	If not 0, FX_NAME should be a valid effect name. 0 if no explosion effect should occur.
	M	FX_TYPE	integer	When the explosion effect should be played. Values: 0 = No effect 1 = When hit 2 = When destroyed 3 = When either hit or destroyed (whichever is first)
	N,O,P	FX_OFFSET	float[3]	3D vector. Offset of the effect system from the pivot of the object. If x == -999.0, the game plays the effect at the point of collision.
	Q	FX_NAME	string	The name of the effect to play.
	R	B-SM	float	How much larger the force needed to smash an object should be than the force needed to break it. In code: smashForce = B_SM * breakForce Smashing always takes precedence over breaking so if smashForce == breakForce, the object will smash and not break. To prevent the object smashing, set a very large value so that it is impossible for the player to achieve the required smash force.
	S	B-VX	float	Offset velocity on X axis. Offset values are added to the velocity from the impact after randomness is factored in.
	T	B-VY	float	Offset velocity on Y axis.
	U	B-VZ	float	Offset velocity on Z axis.
	V	B-VR	float	The maximum deviation from the B-VX/Y/Z values due to randomness.
	W	B-GUN	integer	Object behaviour when shot with a gun. Values: 0 = Immune to gun damage 1 = Breakable 2 = Smashable
	X	B_SPK	integer	Whether sparks are produced on impact (1) or not (0).