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")
• Where do area-effect weapons harm you?
• Damage (Damage to units and terrain)
• Calculating recovery time for injured soldiers
• Accuracy formula
• Reaction fire formula
• 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
• How much does it cost to lose a base
• The dire consequences of picking up unconscious units
• Alien movement patterns
• Secret weapons and items such as Gatling Laser discovered in Item Weight table

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 mine bug - if nobody explodes the proximity mine, something else may explode in the future.
• 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.

Game File Analysis

Not-for-profit-just-for-fun reverse engineering.

• General note re: hex editing game files
• GEODATA - Text for localization.
• GEOGRAPH - Graphics for UFOpaedia and research screen backgrounds.
• MAPS - Pre-generated Battlescape terrain blocks (.MAP). These are filled in with terrain tiles. A few dozen blocks make up a battlescape.
• MISSDAT - Holds the data from the previous mission (Can be exploited)
• ROUTES - Alien route maps (.RMP) for moving around the pre-generated Battlescape terrain blocks.
• SOUND - 1990-era sound drivers, or MIDI files for Windows version.
• TERRAIN - Battlescape graphic tiles for buildings, ships, and terrain.
• UFO2EXE\TACTICAL.EXE - The "Battlescape" program in DOS-release of UFO.
• UFOEXE\GEOSCAPE.EXE - The "Geoscape" program that handles base management and aircraft.
• UFOEXE\BLACK.EXE - The black screen UFO.BAT puts up when swapping between the above two programs.
• UFOGRAPH - Misc graphics (.PCK) for soldier equipment screens, smoke, motion detector blobs
• UFOINTRO - Holds the introduction movie (.FLI) and the endgame pictures (.LBM)
• UNITS - Battlescape graphics for soldiers, aliens, and the pixelated guns they hold. (.PCK and .TAB)
• Stub for the moment - a link to DaiShiva's miscellaneous file formats, including many of the above. Until this section gets fleshed out.

• Saved Game Files including UNITREF.DAT