Leak Age Identification Techniques

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This article is intended to serve as a reference point for methods of estimating the age of files.


Half-Life 2 has had a long and diverse development, and this is heavily reflected in the Leak. From the gradual progression of "side-by-side" texturing to using texture sheets, from Version 27 models to 37, and especially in the sound files that still bear dates of when they were created.


Texture identification isn't the best method, but one thing it is is consistent. There isn't a lot of accuracy, but good estimates are definitely possible to make.

Half-Life 1-esque "side-by-side" Texturing

  • Date: 1999-2001
  • Identification: Observe how the texture looks. Does it look like only one side of the model? Like someone took a photo of the front of it and molded it into a texture? Then it is likely this era.
  • Examples: Odell, Jaytest, Helena Mossman, Police, TBot1, Combot
  • Explanation: Old habits die hard. This is especially applicable with Half-Life 2's developers. In early stages of the game, they used styles of texturing they were very familiar with, which happened to be ones similar to the ones they used in Half-Life 1.

W_-Era folder naming

  • Date: 1999-2001
  • Identification: Does this folder start with W_? If so, it is likely this. Low-resolution textures also help.
  • Examples: The entirety of the "Bathroom" /materials/models/ folder, W_Stalker, the entirety of the "Electronics" /materials/models/ folder.
  • Explanation: Early in Half-Life 2's development, all model foldera were prefixed with W_, possibly meaning "world", like with the world models of weapons. Regardless of this, folders prefixed with this are consistently the most primitive of all the prop models.

Separate Mask Textures

  • Date: 2000-2001
  • Identification: Do the textures of the particular model have "*_mask" textures alongside the normal ones? These look like black-and-white versions of the textures, with the parts intended to be reflective white.
  • Examples: TBot1, the Gasmask Citizen, some earlier textures in Police, the Fast Headcrab's earlier textures.
  • Explanation: Mask textures were a new feature introduced to allow for reflectivity based on a "mask" texture, where the brightest part is the most reflective and the darkest the least. Although they eventually were universally stored in the alpha channels of later textures, they originally were separately kept as their own textures, which shows up in some of the oldest remaining models important enough to warrant them.

Early Facial Textures

  • Date: 2000-2002
  • Identification: Are either of the following textures present in the folder:
  • Examples: Conscript, Odell, Barney
  • Explanation: Before settling on the final, more diverse array of "inside-face" textures, Valve went through a stage between it and the even more primitive HL1-esque mouths and painted-on eyes. Instead of using painted-on eyes, they used irises stuck on a grey sheet, intended to look like an eyeball. Instead of using low resolution mouth textures, they decided to use a higher quality texture.

Separated "Cylmaps"[1]

  • Date: 2002-early 2003
  • Identification: Does this folder have several separated textures for different body parts, such as the arm, torso and leg? Make sure not to include facial features - they remain separated from the main sheet in the final version.
  • Examples: Leak Grigori, Conscript,
  • Explanation: Eventually, even Half-Life 2's modellers modernized and began using cylinder maps for their models. However, it was an entirely different step before they began using sheets as well. Resulting are a pile of intermediate textures with more modern elements than the HL1 models, but that are still lagging behind the final sheets.

"//Original Shader:" VMTs

  • Date: Late 2002 or below
  • Identification: Check the .vmt of a specific texture you are looking at. On the third line, does it contain something like: "// Original shader: BaseTimesLightmap"?
  • Examples: Most textures have this. Just click around a bit.
  • Explanation: At an intermediate point in development, Valve decided to overhaul the shader system, and through an automated script change every .vmt to reflect the new shaders. However, it left behind what the original shaders were. The unintentional result of this is that simply checking the .vmts of any material allows finding out if it is before the "//Original Shader:" period or after it.

Sheeted textures

  • Date: 2003-Retail
  • Identification: For all body textures, does this model use one sheet? Again, eyeball, teeth, iris or such textures do not count.
  • Examples: Alyx, Police (Version 4 and up), Mossman, Kleiner



The Leak possesses a number of different model versions that are still present in the files, ranging from v27 to v37, the current active format.

Leftover Pre-Physics Death Animations

  • Date: 1998-2001
  • Identification: Observe the animations of the model. Is there one dedicated to the model's death, ending in a "dead" state?
  • Examples: Conscript, Combine "Sniper" Elite, Stalker
  • Explanation: Prior to the physics engine being implemented, Half-Life 2 used a system similar to Half-Life: When enemies die, play a death animation, ending in a "idle dead" state. Once the physics engine was implemented and the enemies instead became posed ragdolls upon death, this system was rendered obsolete. Leftovers of it remain in earlier models, however.

Sound Dates

Practically every sound file in the Leak contains internal dates of when they were last edited, which make them very useful.


A list of every file's metadata, including but not limited to date, can be grabbed here. Maintain reasonable caution, though - the dates might be when they were taken from a sound library, not when they were actually implemented. However, it seems you can get accurate dates for certain files that have a _loop suffix, most likely due to being re-edited inside of an audio program to make the sound file loop properly, making it have a new date.

Miscellaneous Files


  • Date: 1999-2000
  • Identification: Go into the textfile, and check to see if the file is there. Beware, though - textures were replaced in Half-Life 2's development. Be careful in making sure the texture fits before assuming it is from this era.
  • Explanation: As mentioned in Hyper Era, oldtrans.txt is a guide for a Perl script, contained in "bin/wadtomaterial.pl", which is the script that was used to convert early WAD-based materials into a later format. It mentions a large number of early location names often unseen elsewhere, such as "urb", "spi", and "hyp".


  • Date: 2000-2001
  • Identification: Go to /hl2/scripts/hl2_scripts.dsp, and open it in a text editor. Have a look around. Does what you are looking for appear in it?
  • Explanation: hl2_scripts.dsp is an index of Half-Life 2's script folder from an early period in development. A number of interesting models are mentioned in it, in particular Sackticks, of which this is one of few of their in-Leak mentions.


  1. Cylinder maps are textures that "go around" the model, rather than look at one side of it.