"I was chomping at the bit to crack the code": How procedural maps became XCOM 2's biggest ambition, after Firaxis couldn't manage it in Enemy Unknown

Garth DeAngelis remembers being successful the country erstwhile Firaxis chose to ditch XCOM: Enemy Unknown's procedurally generated maps. Despite being a diagnostic of the archetypal 1994 game, erstwhile Firaxis tried to physique the tech for their reboot of the turn-based tactical classical 15 years later, it was causing large headaches.

Early experiments were spitting retired levels with trash cans successful the mediate of wheat fields and screen objects placed with nary respect for wherever your soldiers mightiness request them. Good procedural procreation requires finely honed rules telling the machine what tin beryllium placed where, to make spaces that some look believable and play well.

"From what I saw from the team, I didn't deliberation we were ready."

Working retired those rules portion besides learning what makes for a bully XCOM level, creating each the creation assets, gathering each different strategy successful the game, and solving the challenges of getting things similar the caller after-action glam cam to work, risked being 1 hurdle excessively many. The alternate was to nutrient a ample roster of handcrafted maps acceptable successful urban, suburban, and agrarian environments. That way meant Firaxis could guarantee the prime of each map. The downside was that, adjacent with a ample excavation of levels, dedicated players would spot the aforesaid maps cropping up.

In the country determination were champions of each approach, DeAngelis recalls. Jake Solomon, originative manager connected the project, was pushing for procedural generation. He wanted "to springiness the subordinate arsenic overmuch worth arsenic possible, and [make it so] they don't spot the aforesaid happening twice". Art manager Greg Foertsch was warring for handcrafted levels – "He wanted it to look arsenic large arsenic possible".

Despite it lone being DeAngelis's archetypal occupation retired of postgraduate school, aft the 2 directors had laid retired their cases, Solomon called connected him to stock his thoughts. "He's like, 'Hey, you implicit there, kid from New Jersey, what bash you think?'," DeAngelis remembers. "In my heart, I wanted procedural maps. But from what I saw from the team, I didn't deliberation we were ready. Based connected what I saw, the timeline that we had remaining, the deficiency of tools that we had for the pipeline, the things that we were spinning retired did not look good. And I told them that successful the meeting, I thought we had to spell handcrafted."

DeAngelis is speedy to accidental that his dependable unsocial wasn't the crushed Firaxis made the determination to driblet procedurally generated levels successful XCOM: Enemy Unknown – helium says helium was "basically an intern" astatine the time. (Though, arsenic pb shaper connected the game, helium whitethorn beryllium selling himself short.) But soon aft that meeting, the squad went each successful connected handcrafted maps. This wasn't a determination that meant little work. Firaxis had the ambitious extremity of making definite determination were capable maps for 2 playthroughs with nary repeated levels- – much than 70 idiosyncratic maps. It made for galore precocious nights getting XCOM implicit the line.

"One of the things that Garth, Jake and I person successful communal is we similar to plaything big," Greg Foertsch tells me. "Go large oregon spell home." So, adjacent though helium had argued for handcrafted maps successful the room, ditching procedural procreation didn't beryllium good with him oregon the others. When 2K gave the greenlight connected XCOM 2, cracking procedurally generated maps was apical of everyone's agenda.

Image credit: 2K Games / Firaxis

"I was chomping astatine the spot to ace the codification for procedural maps," DeAngelis says, but it wasn't simply that the squad astatine Firaxis wanted to situation themselves, though. "We wanted to astonishment the player, and we knew excessively that the XCOM assemblage would devour up procedural maps if we could nail it and marque it consciousness right."

While the bulk of the XCOM squad worked connected Enemy Within, the 2013 enlargement to Enemy Unknown, a tiny radical divided disconnected and began accumulation connected an ambitious sequel. "We were capable to commencement the improvement successful parallel," DeAngelis says. "I was capable to peel disconnected a onslaught squad with Greg, Jake, and others to commencement prototyping procedural maps for XCOM 2."

"Having that clip betwixt XCOM and XCOM 2 to conscionable beryllium down and benignant done what we had learned by doing it the incorrect mode the archetypal clip was useful," Greg Foertsch, XCOM 2's creation manager says. "I felt similar I knew however to bash it now, it was conscionable a span excessively acold for the archetypal one."

"It was conscionable a span excessively acold for the archetypal one."

The main situation was defining a ruleset for wherever to spot rooms, objects, and screen that would some marque for a amusive representation to play and a believable 1 to look at. The rules didn't conscionable person to enactment successful 1 environment, they had to representation onto urban, suburban, and agrarian maps. Where a autobus halt mightiness marque a bully portion of screen successful 1 map, it shouldn't beryllium successful a agrarian environment, truthful an equivalent entity had to beryllium found. Foertsch remembers the tiny squad spending agelong days "just trying to fig retired the rules of the procedural system, and however could we marque a ruleset that spanned each of those 3 precise antithetic ocular spaces and inactive marque sense."

Another wrinkle successful the situation was destruction. In some the archetypal X-Com and the XCOM: Enemy Unknown reboot, the walls and floors of buildings and galore screen objects are destructible. If a muton is ducked down down a model successful a country store taking potshots astatine your squaddies, you tin fling a grenade their mode and stroke a large large spread successful the wall, exposing the alien to fire. There was nary question demolition would instrumentality successful XCOM 2, but it raised questions of what to bash if a procedurally generated representation stuck 2 buildings backmost to back. Would destroying an adjoining partition successful 1 destruct the other? Would it look awkward and messy?

Firaxis's solution was thing they called the 'plot and parcel' system. Each representation successful XCOM 2 is divided into a grid of plots, and these plots tin beryllium filled with parcels of preassembled assets. No buildings were straight adjacent to each different due to the fact that of a bladed abstraction betwixt each parcel. "Think astir that arsenic if you're playing tic tac toe," Foertsch says. "If you adhd thickness to the lines that gully the board, it gives you a buffer betwixt 1 compartment to the adjacent cell."

That attack made for much absorbing playable levels, but to look similar a natural, coherent whole, the squad had to absorption connected blending the gaps betwixt the parcels. "We went from having a representation wherever we conscionable popular down random screen elements [where] there's truly nary worth successful that," Foertsch says, to maps wherever the blending assets were selected by the parcels successful neighbouring plots. "Whatever drops down successful [a plot] tin drastically alteration the 1 that's successful the adjacent one. That allowed america to acceptable up rules that made consciousness and visually didn't [create] a weird space." It's a strategy Firaxis continued to usage successful the XCOM bid and recreated for its Marvel tactics crippled Midnight Suns.

The squad avoided maps turning into a azygous grid by varying the size of plots. "There were 3 antithetic sizes," Foertsch says. "There were XCOM units, which were similar a metre and a fractional each. So 16x16, 16x32, and 32x32." Within an municipality map, this meant you mightiness travel crossed a ample petrol presumption sandwiched betwixt a enactment of tiny quadrate houses connected 1 broadside and a agelong bladed publication store connected the other, with roads, autobus stops, parkland benches, and thoroughfare signage giving the antithetic buildings the look of each being portion of 1 handcrafted environment.

Image credit: 2K Games / Firaxis

While it mightiness dependable straightforward, it wasn't casual to replicate. Foertsch heard from the squad astatine Splash Damage moving connected Gears Tactics that their procedural strategy didn't person the gaps betwixt parcels. "They had problems," Foertsch says. "How bash you sew those 2 things unneurotic if there's nary in-between?"

When enactment connected Enemy Within was completed and the larger squad began to determination onto the project, Foertsch handed disconnected the crippled and parcel strategy to the level designers and they took it overmuch further than helium imagined. "They started adding procedural chunks everyplace wrong of the plots, too, truthful on those small lines, there's antithetic streets and antithetic thoroughfare corners and antithetic cover. Everything ended up dialing up times 1000 astatine that point."

Foertsch calls retired the enactment of "exceptional" Brian Hess successful particular. Joining the squad arsenic a level decorator connected the Enemy Within expansion, Hess became pb level decorator connected XCOM 2 where, Foertsch says, helium was "the 1 who mostly took it to the last version, [and] added each sorts of brainsick worldly to it." In 2018, Hess gave a speech astatine GDC that reveals the complexity of the rules underpinning each representation generated successful XCOM 2.

Image credit: 2K Games / Firaxis

As good arsenic managing XCOM 2's development, creating schedules crossed the squad to marque definite each the many, galore tasks that marque up a crippled were being completed, DeAngelis was successful the wont of staying precocious into the nighttime playing the latest physique to stock notes with the squad the adjacent day. "I loved the crippled truthful much, I made definite I played the heck retired of it continually," helium says. Those aft hours play sessions meant DeAngelis was 1 of the archetypal radical to spot XCOM 2 coming together. He remembers, for instance, the archetypal clip helium was capable to chopped 1 of his soldiers escaped from the suffocating coils of an alien viper with his ranger's machete, and telling the squad to "hear and spot their reactions".

DeAngelis besides remembers different night. "It's 1am successful the morning, and I'm playing this happening aft my mean enactment hours and meetings," DeAngelis says. What helium was seeing connected the surface wasn't arsenic melodramatic arsenic an alien viper, oregon a caller quality class, oregon ngo type. But, for the idiosyncratic who was successful the country erstwhile they decided reaching for procedural procreation successful XCOM: Enemy Unknown was beyond their grasp, it was possibly much significant. He remembers looking astatine the level earlier him and reasoning "Damn, this metropolis centre procedural map… I'm a believer."