Under The Hood

Information in this section cracks open the bonnet and attempts to explain the how and why questions on a variety of aspects of the inner workings of the games, such as formulas and other odds and ends like reproducible game bugs or useful 'glitches'. (Note this does not include technical bugs)

As we don't have the source code, quite a lot of the information here is derived the traditional way, with paper, pen and lots of free time.

Note: It is hoped that the following articles will be incorporated into their related sections at a later date - where and when ever possible (reactions under stats, phantom radars under general radar information, etc). Also duplicate entries will need to be cleared out.

General

• Radars - how they work, and why build only one of each type. (Plus, the phantom radar "trick")
• Craft Combat Mechanics
• Where do area-effect weapons harm you?
• Damage (Damage to units and terrain)
• Calculating recovery time for injured soldiers
• Accuracy formula
• Reaction Mechanics
  • Reaction fire formula
  • Reaction fire triggers
  • Reaction Fire Weapon Preference
• Motion scanner blip sizes
• Psionics - How a psionic attack works
• Throwing distances
• Item weights and how they correlate with Strength
• Weapon comparison tables
• Unit spawn priorities

Unit spawn in the following order: HWPs, X-Com units, aliens, alien terror units, civilians. The player and the AI are allocated 40 slots respectively in the unit table. If there are too many units that precede later units, the order the units spawn will go according to the spawn priority above, and any later units will be dropped off the list. For example, if there are 8 HWPs and 10 soldiers, the HWPs will take up the first 32 of the 40 slots, leaving room for only 8 of the 10 soldiers.

• How much does it cost to lose a base
• The dire consequences of picking up unconscious units
• Alien movement patterns
  • You may also be interested into looking at some theories about the Tactical AI.
• How the AI uses Inventory
• Secret but incomplete weapons and items such as Gatling Laser discovered in Item Weight table
• Destroying Terrain
• External UFO Windows

Useful Glitches, Workarounds or Just Plain Odd Stuff

See also Exploits

• Free Ammo for tanks on Base Defense missions
• Straight lines and the equator - getting a little more range from your ships with the Great Circle Route
• Stacking bug (UFO only) and Activating Melee Attacks - see Stun Rod notes
• The Medi-Kit heal-through-wall trick
• Hitting multiple targets with incendiary effects
• The oddities of data corruption
• The oddities of mind control/molecular control
  • Why civilians go rogue
  • Large units and Psionics
  • Gaining permanent control of a Chryssalid/Tentaculat
  • Zombie's patented permanent mind control by stunning technique
• Spawn locations in Base Defense missions and how to make the ultimate "hands off" base.

Not so useful Glitches

See also Known Bugs.

• Glitches with the Gauss SWS (TFTD only)
• Ufo Names in Tftd (TFTD only)
• Vertical waypoint bug (Collectors Edition only) - Blaster bombs go south instead of straight down.
• Proximity grenade bug - if an armed proximity mine does not explode, something else may explode in future missions.
• Disappearing ammo bug - partly used clips are discarded. XCOMUTIL fixes.
• Ctrl+C - why it does what it does and why you shouldn't exploit it. (DOS versions only, where GEOSCAPE and BATTLESCAPE are separate programs connected by a batch file.)
• "My body is a weapon" - Corpses sometimes contain an ammo clip. This can happen when a weapon is destroyed which had ammo loaded into it. When a unit dies, the corpse created takes the now vacant item slot. The ammunition is still registered as being loaded into that item slot, however, and appears to be inside the newly created corpse. (Can clips in destroyed weapons be recovered at end of combat?)
• Unresearched alien weapons can not be thrown. (Items need a weight to be thrown, and you don't know its weight until you research it.)
• February has 31 days in all years other then the first.

See Also

• Game Files