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 reproduceable 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 only one of each type will ever function. (Plus, the phantom radar "trick")
• How the grenade timer works
• Where do area-effect weapons harm you?
• Damage formula (Weapons vs Armor)
• 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
• Why Strength does NOT improve with more weight.
• Weapon comparison tables
• Fire. Just how does it work?
• Unit spawn priorities
• How much does it cost to lose a base - And why you shouldn't put up a fight if there really is no hope of winning. (It's not as bad as it sounds. Really!)
• The dire consequences of picking up unconscious units
• Alien movement patterns

Useful Glitches, Workarounds or Just Plain Odd Stuff

See also Exploits

• Free Ammo for tanks on base defence missions

-Basically, your all your tanks will be fully armed for these, even if you didn't have enough ammo for them in the first place. Very useful for Hovertank/Launchers...

• Phantom Radar - How to get rid of the radar, but keep its abilities
• Straight lines and the equator - getting a little more range from your ships
• Stacking bug (UFO only) and Activating Melee Attacks - see Stun Rod notes
• The Medikit heal-through-wall trick
• Exploits#Throwing through ceilings - Throwing items through the ceiling trick
• Consequences of firing explosives at the ceiling

-The explosive will hit the ceiling... BUT the ceiling is actually the "floor" of the level above. So, the explosion will occur on the level above you! hmm.

• Hitting multiple targets with incendiary effects
• The oddeties of data corruption
• The oddeties of mind control/molecular control
  • Why civilians go rogue
  • Large units
  • Gaining permanent control of a Chryssalid/Tentaculat
• On spawn locations in base defence missions and how to make the ultimate "hand's off" base.

Not so useful Glitches

See also Known Bugs.

• Glitches with the Gauss SWS (TFTD only)
• Ufo Names in Tftd (TFTD only)
• Exponential transfer costs - don't keep clicking the transfer button.
• 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" - Alien corpses sometimes contain an ammo clip. Probably another case of data corruption
• Unresearched alien weapons can not be thrown.
• Transfer limit cash eater - Only 100 items can be in transit at a time. (Here, a transfer of e.g. 200 Elerium counts as one "item". Also, all soldiers are counted individually.) If you go over the limit, you will get a warning that there is no more transport capacity. If you STILL try to transport something after getting the warning, the item will stay where it is, but the transportation cost still gets deducted.

Game File Analysis

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

• General note re: hex editing game files
• GEODATA - Text for localization (eg ENGLISH.DAT, GERMAN.DAT)
• GEOGRAPH - Graphics such as backgrounds for research screens (.SCR).
• MAPS - Pregenerated Battlescape terrain blocks (.MAP). These are filled in with terrain tiles. A few dozen blocks make up a battlescape.
• MISSDAT\DUM.BIN - placeholder
• ROUTES - Alien route maps (.RMP) for moving around the pregenerated Battlescape terrain blocks.
• SOUND - 1990-era sound drivers.
• 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 pixellated guns they hold. (.PCK)
• Saved Game Files