A .zip file used for a ZDoom mod is given the .pk3, .pkz, .pke or .ipk3 extension instead of .zip. This helps avoid confusion and prevents Windows from presenting it as a directory. ZDoom supports stored, shrunk, imploded, deflated, bzip2 and LZMA compression algorithms. Compressed archives have advantages over WADs: smaller file size due to compression, greatly reduced memory usage, and proper directories instead of namespaces.
PK3 files are used by ZDoom, an application for Doom, Heretic and Hexen. They can also be used by Sonic Robo Blast 2, a Sonic game. SRB2 started using 2.2 PK3s instead of .SRB to store resources. SRB2 uses PK3s to store games-ons and Doom WADs.
PK3s are Zip-compressed packages containing graphics, sounds, maps and game data. They are related to ZDoom, a family of enhanced Doom ports for modern operating systems.
Since PK3s use Zip compression, they can be extracted using WinZip or PKZIP. Quake III PK3s should be in quake3/q3ut3, quake3/baseq3 or quake3arena/q3ut3. Games using the id Tech 3 engine include Quake III Arena, Jedi Knight II, Soldier of Fortune II, Return to Castle Wolfenstein and Call of Duty Classic.
To open a PK3 file, you need suitable software like ZDoom. Without it, you will get an error saying Windows cannot open the file. To choose another app to open it, right-click the PK3 and select Open With, then choose another application. You can also drag the PK3 onto a browser window to view it directly.
To open a .PK3 file, use a .PK3 reader like ZDoom or other software. Once installed, you can open .PK3 documents. To create .PK3 files yourself, use ZDoom or other PK3 creating software.
Quake III Arena