The X-ray engine uses GSC Gameworld's proprietary ALife artificial intelligence engine. ALife supports more than one thousand characters inhabiting the Zone. These characters are non-scripted, meaning that AI life can be developed even when not in contact with the player.

The NPCs have a full life cycle (task accomplishment, combat, rest, feeding and sleep) and the same applies to the many monsters living in the Zone (hunting, attacking Stalkers and other monsters, resting, eating, sleeping). These monsters will migrate in large groups. The non-scripted nature of the characters means that there are an unlimited number of random quests. For instance, rescuing Stalkers from danger, destroying Stalker renegades, protecting or attacking Stalker camps or searching for treasure. The AI characters travel around the entire zone as they see fit.

Numerous tactics can be employed to complete the game, such as rushing or using stealth and sniping. The NPCs will react in a different way to each of them. S.T.A.L.K.E.R.'s NPCs plan ahead by "Goal-Oriented Action Planning" in order to achieve this.

Bullet physics

S.T.A.L.K.E.R. uses "realistic" bullet physics, similar in nature to tactical shooters such as Ghost Recon Advanced Warfighter or Operation Flashpoint. Bullets are affected by gravity, bounced against solid surfaces at oblique angles, and firearms are highly inaccurate when fired without aiming. To score consistent hits at medium or long range, players must aim using the iron sights
on their guns. Additionally, hit damage is pseudo-realistic, and the player can die after only being shot a few times (although later in the game various armor suits and artifacts can be acquired that increase the player's resistance to damage). Late-game depends heavily on scoped weaponry due to the well-armed and powerful enemies that keep their distance from the player.


S.T.A.L.K.E.R. uses a heavily modified version of the ODE physics engine, supporting hundreds of physics objects on different levels. Ragdoll physics, destructible objects, realistic bullet ballistics and skeletal animation can all be found in the game.


A weather system is integrated into various parts of the landscape and allows a variety of weather effects, such as sunshine, storms and showers. The weapons available, behavior of the AI, game tactics and ranking systems will depend on the weather.

For more direct specifications, check the engine's homepage.

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Wandering in stalker russian forum, i found that developers of OLR were still working on this mod (ORL 3.0 has never been so close...).
So here is the latest patch (it's true this time) since it came out a few days ago (21/10/2018).

Gathered on Gameinator forums:
Gameinator: Oblivion Lost Remake 2.5

Important informations

This patch NEEDS Stalker OLR 2.5 + fixx19 (or above).
English translation update also available (v0.9.6) for this patch (previous patches NOT compatible).
A NEW GAME is required.

Please read instructions on each file page.

Download links (in that order)

Full base version with fixx17:
S.T.A.L.K.E.R. Oblivion Lost Remake 2.5.17 Part 1
S.T.A.L.K.E.R. Oblivion Lost Remake 2.5.17 Part 2

Fixx17 to 19 patch:
Stalker OLR 2.5 Patch fixx17 to 19

Fixx19 to 21 patch (this patch, the latest, for the moment):
Stalker OLR 2.5 Patch fixx19 to 21

Latest english translation (v0.9.6 NEEDED, previous versions NOT compatible):
Stalker OLR 2.5 English translation v0.9.6

Note that language patches below 0.96 must NOT be installed (due to changes in fixx21).

If you have installed language patch 0.95 for example, you'll probably have to redo a full install (in the order listed above) to play with fixx21 + language patch 0.96.

Major changes since Fix19:

  • Performance optimization
  • Vehicle Refactoring
  • Light optimization and fixes
  • "Camera swinging" effect
  • Animations and map fixes
  • Many others bug fixes (tasks, dialogs...)

See Stalker Oblivion Lost Remake 2.5 Fixx19 article to view previous changes.

Some screenshots




Full list of changes since Fix19

(Google translated, sorry...)

fixx 21
minor tag changes in xml in gameplay

fixx 20
color scaled options preset buttons added to video options
added color fringe effect along the edges of the reticle and binoculars
editing script failures when certain characters are called by the PDA
fixed cam_fov reset after splash screen on Yantar
edit the invisible snap on the statics in the dungeons of Amber
edit the invisible snap on the statics on the MedPribor
fixed minor quests from Toad to eliminate stalkers
Fixed the inclusion of NPS lanterns in the premises
after the journalist removed unnecessary documents
edit tag duplication in xml in gameplay
added indication of Elder's pit
editing the task dialog with rafik
trumpet update
optimization of F-1 grenades
minor text edits

fixx 19.9
due to complaints of microfreeze, the editing of spawn empty boxes has been canceled

fixx 19.8
edit description of overalls EX-04
restored Rostock on the global map

fixx 19.7
updated news layout
Editing of position on the map on the Cordon
Edit potential relegation on the Cordon and Medpribor
compatibility of updated transition points from Bar with old saves
minor text edits

fixx 19.6
Fix icon Professor in the message in Pripyat
fix light sources on earth
minor text edits

fixx 19.5
menu is aligned with moral and ethical standards

fixx 19.4
edit reset the parameter "camera buildup"
Edit pys-bug with the texture of the crow
Added quick boot information to management options.
quick save information added to management options
option added item "show coordinates"
optimization option for 12-core processors added to configurator
minor text edits

fixx 19.3
edit random spawns empty boxes by levels
edit the lack of proposals on the transition Bar-Quiet Hills
Edit teleport on the transition Bar-dump
"camera swinging" added to advanced video options
edit the effects of burer steps
edits of management frets and fields
edit "optimized" rain in the configurator
edit recommendations for rain and smoothing in the configurator
minor text edits

fixx 19.2
editing lighting trees in static lighting
static lighting fixation
editing over-shading in static lighting
editing of water with duckweed on static lighting on Nvidia video cards
"Lanterns on statics" added to advanced video options (r1)
edits of chimera steps effects
edit animations FN2000
minor text edits

fixx 19.1
edit scaling terrane Yantar
editing vodka parameters
Editing the shadow of the trunk
restoration of cornflowers in the Bar
edit AKM description in the encyclopedia
Drunk treats (need a new game)
edit lags when approaching the bar and the vegetable base (need a new game)
slightly increased jump gg
voice of Elders
edit departure when searching the trunk
edit the safe in the Dark Valley (need a new game)
suffocating the plague zombie
edits of swinging / throwing grenades in running
edit the effects of flesh steps
edit the effects of footsteps and amber builders attacks
off the side psi effect in amber bildopolter
editing the single-channel sound of the first explosion of a helicopter
fixed object box materials
edit nps view through two-wheeled trailers (need a new game)
edit nps view through darklebe doors (need new game)
edit nps view through the door of the journalist (need a new game)
helicopter build
edit and optimize the interaction of materials
added vehicle condition scale
edits of potentially problematic military models
added damaged versions of all cars
car camera edits
vehicle refactoring *
name edits for anomaly detectors
price editing for elite anomaly detector
editing the price of the artifact "Plasma"
improved texture of tree trunks, the moon, etc.
the extra option "illumination from the rays" is disabled (r2 or r2a)
updated bump fret
hey in the car is hardly noticeable for monsters and NPS (need a new game)
the chapter on transport has been added to the PDA encyclopedia (new game is needed)
edits generated NPS names (need a new game)
Increased the vitality of the journalist (need a new game)
edits of the encyclopedia interface in PDA
Build water added to configurator also for Cordon and Silent Hills (r1)
minor text edits
fix long jump in the car **
* Note: when loading old saves, decorative transport models may not be displayed correctly.
** Note: the purchased btr is now functional only with a new game, when loading old saves it will be unavailable for landing.

Stalker Oblivion Lost Remake 2.5 Fixx19
S.T.A.L.K.E.R. Build 1935

Stalker Oblivion Lost Remake 2.5 Fixx19

S.T.A.L.K.E.R. Build 1935 2 comments

Patch 17 to 19 for Stalker OLR (build 1935) 2.5 available! English translation update also available. Originally created by Macron and hi_flyer.

Hexagonsphere 3.1 - Now with 50% more of the same
S.T.A.L.K.E.R.: Call of Pripyat

Hexagonsphere 3.1 - Now with 50% more of the same

S.T.A.L.K.E.R.: Call of Pripyat 8 comments

A new update to this polarizing, but humble graphic addon for S.T.A.L.K.E.R. games.

S.T.A.L.K.E.R. Call of Chernobyl - New Reshade 2017
S.T.A.L.K.E.R.: Call of Pripyat

S.T.A.L.K.E.R. Call of Chernobyl - New Reshade 2017

S.T.A.L.K.E.R.: Call of Pripyat 28 comments

This 2017, a new Reshade preset... And something more. For S.T.A.L.K.E.R. Call of Chernobyl.

S.T.A.L.K.E.R Optimizer Release 1.0
S.T.A.L.K.E.R.: Clear Sky

S.T.A.L.K.E.R Optimizer Release 1.0

S.T.A.L.K.E.R.: Clear Sky 10 comments

Information on the next release of the S.T.A.L.K.E.R. Optimizer, list of features and news.

Add game Games
S.T.A.L.K.E.R.: Call of Pripyat

S.T.A.L.K.E.R.: Call of Pripyat

First Person Shooter

Call of Pripyat takes you once again into the vicinity of the Chernobyl nuclear reactor that exploded in 1986. This so-called "Zone" is a highly contaminated...

S.T.A.L.K.E.R. Shadow of Chernobyl

S.T.A.L.K.E.R. Shadow of Chernobyl

First Person Shooter

In 1986, the world's worst nuclear disaster occurred at the Chernobyl power station. Soviet authorities established a 30km 'Exclusion Zone' around this...

S.T.A.L.K.E.R.: Clear Sky

S.T.A.L.K.E.R.: Clear Sky

First Person Shooter

A group of stalkers, for the first time, reaches the very heart of the Zone-the Chernobyl Nuclear Power Plant-and triggers a cataclysm on the brink of...

S.T.A.L.K.E.R. Build 1935

S.T.A.L.K.E.R. Build 1935

First Person Shooter

This is build 1935 of S.T.A.L.K.E.R. Shadow of Chernobyl, formally called S.T.A.L.K.E.R. Oblivion Lost. This was made by GSC Game World before they remade...

S.T.A.L.K.E.R: Oblivion Lost

S.T.A.L.K.E.R: Oblivion Lost

First Person Shooter

Ones of the first concepts of S.T.A.L.K.E.R Shadow of Chernobyl.

Comments  (0 - 10 of 67)

Tirando o motor gráfico X-Ray que tem problemas gráves, a sério stlaker é exelente.

Reply Good karma Bad karma+1 vote

stalker is the best game series ever :) i even like it more then Half Life series.

Reply Good karma Bad karma+5 votes

I missed Stalker 2 :( I want stalker 2 why did it has to been cancelled
can like someone make stalker 2 as mod or game cause i have to play survarium that Ex-stalker 2 dev make now

Reply Good karma Bad karma+3 votes

todos nós queremos S.T.A.L.K.E.R 2, o jogo seria bem-vindo na comunidade e para a empresa, seria uma fonte de lucro pois a cominudade de stalker é muito grande, mesmo sendo um jogo antigo, ainda tem muito a oferecer

Reply Good karma Bad karma+1 vote

S.T.A.L.K.E.R. is confirmed. Here are their new homepage .

Reply Good karma Bad karma+1 vote

thx for information

Reply Good karma Bad karma+1 vote

x-ray is a great engine and probably the most capable engine I have ever seen.
Sadly though it is hard on the proccesor and RAM.

This mod/addon/whatever will bring updated engine with multicore support and fixed freezes:
The developers got X-RAY source code...

Their_FA wrote: Q: What kind of patch will be needed?
A: Lost Alpha is based on a beta patch, called 1.0007. This was never released to the public, but we had the opportunity to get it, and fix it up. The engine is now totally upgraded, runs better than ever. This means, you don't need any SoC patches for LA, since now it became a standalone (but still free) game.

Reply Good karma Bad karma+3 votes

Best game engine on the PC.

Reply Good karma Bad karma+4 votes


Reply Good karma Bad karma0 votes

This is great game engine.

Reply Good karma Bad karma+1 vote
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Highest Rated (4 agree) 10/10


Mar 23 2011 by .sverek

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