Vehicle damage scaling factor

The Vehicle damage scaling factor world option (VEHICLE_DAMAGE) controls how damaged pre-spawned vehicles are. It ranges from 0.0 to 4.0 in steps of 0.1, and defaults to 1.0.

When it applies

The option only affects vehicles spawned with a non-mint status, i.e. status of -1 (light damage, the default) or 1 (disabled). See Spawning vehicles. Vehicles spawned with status: 0 are always intact.

Each vehicle part is rolled independently, so one vehicle usually has a mix of intact, damaged and broken parts.

How the roll works

For every part, the game computes two thresholds from the option value (chance) and rolls 4d8:

int broken = 8 * chance;  // truncated toward zero
int unhurt = 20 * chance; // truncated toward zero
int roll = dice( 4, 8 );  // 4..32, bell-shaped, mean 18

Condition	Resulting part HP
roll >= unhurt	100% (intact)
broken < roll < unhurt	(roll - broken) / (unhurt - broken) of durability
roll <= broken	0% (broken); batteries and fuel tanks are also emptied

Things to note:

• Raising the option moves both thresholds up, so more of the bell curve falls into the damaged and broken ranges.
• A damaged part never keeps 100% HP. Its highest HP is 1 - 1 / (unhurt - broken), so HP jumps to 100% at roll == unhurt.
• Values below 0.25 leave unhurt at 4 or less. Since the lowest possible roll is 4, no damage happens at all.
• At 4.0, broken is 32, which is the highest possible roll. Every part of a damaged vehicle is broken.

Reference values

Factor	broken / unhurt	Broken	Damaged	Intact	Expected HP
0.0	0 / 0	0%	0%	100%	100%
0.5	4 / 10	0.0%	3.1%	96.9%	99.0%
0.8	6 / 16	0.4%	29.5%	70.1%	89.9%
1.0	8 / 20	1.7%	60.7%	37.6%	75.0%
1.5	12 / 30	12.0%	87.6%	0.4%	34.4%
2.0	16 / 40	37.6%	62.4%	0%	12.5%
3.0	24 / 60	91.9%	8.1%	0%	0.5%
4.0	32 / 80	100%	0%	0%	0%

Interactive chart

Try any other value with the chart below. Each row is one possible 4d8 result, from the highest roll at the top to the lowest at the bottom. The bar length is the chance of that roll, and its color is the outcome:

• Intact: light green.
• Damaged: green, yellow-green, yellow, orange or red, one color per 20% of remaining HP.
• Broken: gray, like broken parts in the vehicle interface.

Older worlds

Before the range was reduced to 0.0-4.0, the option accepted values up to 10.0. Anything above 4.0 already broke every part of a damaged vehicle. A world saved with a value outside the new range loads with the default value 1.0 instead.