Wrecks and Heaps

A destroyed unit can leave a wreck, a smaller heap or nothing at all. The choice is not random. It depends on how violently the unit died.

Severity

When a unit dies, the game rates its death with a number from 1 to 100, the severity. It is the average of two percentages:

  • how far the killing blow took the unit below zero hit points, as a percentage of its maximum;
  • the unit's health one to two seconds before it died. The game samples each unit's health once a second.

Each unit's death script turns the severity into a corpse. 244 of the game's 256 death scripts use the same three bands:

Severity Corpse
25 or less Wreck
26 to 50 Heap
Over 50 Nothing

A unit worn down by small hits leaves a wreck, because its health was already low a second earlier. A healthy unit destroyed by one large hit leaves nothing.

The Chain

Each wreck in the data names the feature it turns into when destroyed, normally a heap, and the heap names nothing. When a death falls in the heap band but the unit's wreck has no heap, the unit leaves nothing. This is true of 65 units, almost all of them ships, submarines, hovercraft and buildings that stand in water.

Most wrecks hold 80% of the unit's metal cost, and most heaps hold half of that, 40%. Most wrecks block movement, while heaps almost never do.

Wrecks have hit points. Each explosion that reaches a wreck adds the weapon's basic damage to it, with no reduction for distance. When the total reaches the wreck's hit points, the wreck turns into its heap, and a heap destroyed in the same way disappears. Wrecks in Total Annihilation do not rot: a wreck stays until it is reclaimed or shot away.

Unit Metal cost Wreck metal Wreck hit points Heap metal
Peewee 53 42 200 21
Flash 106 85 500 43
Solar Collector 145 116 261 58
Bulldog 467 374 1682 187
Fusion Reactor 5130 4104 2480 2052
Big Bertha 4184 4147 1440 2074

The Big Bertha is an exception: its wreck holds 99% of its metal cost.

When There Is Never a Wreck

  • Commanders, aircraft, crawling bombs and mines have no wreck in the data.
  • A unit that was not finished never leaves one.
  • A unit that is reclaimed or captured leaves none.
  • If the ground where the wreck would lie cannot be cleared, for example because of an indestructible feature, the wreck is not placed.

Worked Example

A Flash has 625 hit points:

How the Flash dies Below zero Health a second earlier Severity Leaves
Worn down by Peewee fire: the last 8-damage pellet hits it at 1 hit point 7, which is 1% 10% 5 Wreck, 85 metal
At 250 hit points for over a second, then hit by a Guardian shell for 360 110, which is 17% 40% 28 Heap, 43 metal
At full health, hit by a Big Bertha shell for 2000 1375, which is 220% 100% 100 Nothing
Hit by the Commander's D-gun for 30,000 far over 100% any 100 Nothing

This is why the D-gun leaves nothing to reclaim. Its 30,000 damage puts any unit far below zero, so the severity is always at its maximum.