Physics Props

Physics Props

rally_scripted_object places props in your map, such as cones, barrels, hydrants and crates. They can be static or movable, and destructible or indestructible.

Script files

A prop can be described in a .script file, usually in scripts/. The entity's script key points to it, for example "script" "scripts/hydrant". The .script extension is added automatically. The repository contains an annotated example: baseq3r/scripts/example.script.

rally_scripted_object
{
	model "hydrant"                 // model block (see below)
	deadmodel "waterspray"          // model after it's destroyed
	moveable 0                      // 0 = static, 1 = movable
	mass 50
	health 1000                     // see "Health" below
	mins "-8 -8 -8"
	maxs "8 8 8"
	presound "sound/hydrant/metalcreak"         // looped until destroyed
	hitsound "sound/hydrant/solidmetalbang"     // when hit
	destroysound "sound/hydrant/solidmetalbreak"
	postsound "sound/hydrant/waterspray"        // looped after destroyed
	gibs                            // up to 5 gib models
	{
		"models/mapobjects/hydrant/piece1" -3   // negative = random up to this many
		"models/mapobjects/hydrant/piece2"  2
	}
}

Model blocks in the same file define the MD3 and its animation frames:

hydrant
{
	model "models/mapobjects/hydrant/hydrant"
	damageframes "0 4"      // frame for no damage ... full damage
}

Setting properties on the map entity 🧪

Development build. You can set the physical properties directly on the entity in Radiant. They override the values from the script. A script is optional: for a simple prop, a model key is enough.

{
"classname" "rally_scripted_object"
"model" "models/mapobjects/cones/cone01.md3"
"origin" "256 128 32"
"angles" "0 45 0"
"physics" "dynamic"
"mass" "4"
"elasticity" "0.2"
"friction" "0.7"
"mins" "-4 -4 -8"
"maxs" "4 4 8"
"health" "0"
}

Key	Range / default	Description
model		MD3 model path (used when there's no script)
script		Optional script file, e.g. scripts/hydrant (.script is added automatically)
physics	static / dynamic	static = solid but doesn't move. dynamic = gravity, collisions, rotation. (Replaces the old moveable 0/1, which still works.)
mass	1 – 100000	Mass
elasticity	0 – 1	Bounciness
friction	0 – 4	Contact friction
rolling_friction	0 – 1	Resistance against rolling
spinning_friction	0 – 1	Resistance against spinning
inertia_shape	box	Shape used for rotation physics: box, sphere, cylinder_x, cylinder_y, cylinder_z
vehicle_impact_scale	0 – 2	How strongly cars push the prop (🧪 up to 2)
radius 🧪	units	Makes the prop a ball: centred bounds, sphere collision and sphere inertia. Overrides mins/maxs.
collision_shape 🧪	auto / box / sphere	Forces the collision shape
vehicle_vertical_scale 🧪	0 – 1 (1)	Flattens car hits: scales the upward share of the contact
vehicle_lift 🧪	0 – 0.9 (0)	Minimum upward share of every car hit
max_speed 🧪	units/s (0 = none)	Speed cap
never_sleep 🧪	0 / 1	1 keeps the prop simulated even when it lies still
weapon_impact_scale	0 – 5	How strongly weapons push the prop
health	0 = indestructible	Damage the prop can take before it's destroyed
mins / maxs		Collision box in local coordinates. Make it fit the visible model.

Health

• health above 0: the prop can be destroyed and switches to its deadmodel, gibs and sounds.
• health 0 (or the legacy -1): indestructible.

ℹ️ In v0.7d, -1 means indestructible and 0 means the prop breaks on the first impact. The development build treats both 0 and -1 as indestructible.

Collision

Dynamic props are simulated on the server in fixed steps and sent to all clients. Collision uses a simplified shape, not the full render mesh. If no collision hull can be built from the model, the mins/maxs box is used. Always set mins and maxs so they match the visible model.

Tips

• The Autoball ball 🧪 is a physics prop too (autoball_ball); its keys are the same as above.

• Use static props for heavy obstacles that shouldn't move, and dynamic props for cones, barrels and boxes.

• Don't overdo it. Every dynamic prop costs server time and bandwidth.

• Props near the racing line make great chaos, but keep them out of the way on the start grid.