BSPSource

Screenshot of BSPSource.

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BSPSource is a GUI map decompiler for Source games, written in Java.

Based on VMEX, it converts BSP files into VMF ones that can be loaded in Hammer. It also includes numerous bug fixes over VMEX and new features for doing the conversion, such as extracting embedded assets, processing multiple BSPs at once, and more.

Bug:Newer version (starting with 1.4.4 or later) may not launch^[1] on some systems (especially with systems with Windows 11 or localized version of the OS). Users can try to install latest version of Java and download the bspsrc-jar-only.zip version and run the bspsrc.jar file, or alternatively, use older version of BSPSource, or downgrade/upgrade/reinstall Windows.  [todo tested in ?]

Note:Due to technical reasons, decompiling maps doesn't accurately recreate their original VMF state, often presenting issues such as invalid geometry solids, tools textures such as NPC Clip or Player Clip all replaced with either Nodraw or entirely replaced with NPC Clip or Player Clip which cause lighting issues or NPCs to get stuck, or misplaced areaportal brushes in the decompiled file.

Workaround:Decompiling the file again or more times may generate better results, such as avoiding some of these issues^[Why?].

Note:If there is decompilation protection present, the conversion may be more difficult to work with.

BSP with File Packing

In the tab "Other" set tick in in "Extract embedded files". Then put downloaded files in game directory.

BSPInfo

BSPInfo is a mode of BSPSource that instead of decompiling .bsp files, analyses them. Content such as: bsp version, compression type, checksums, AppID, lumps and compile parameters. It can also extract embedded files similarly to GCFScape.

See also

• Half-Life Unified SDK Map Decompiler - GUI map decompiler for GoldSrc

External links

• BSPSource on GitHub
• Latest Java (optional, for 1.4.4 or later. This is only required if you are using bspsrc-jar-only.zip (which does not have Java bundled in.)
  • After installing, try to run the bspsrc.jar executable, or type javaw -jar "C:\your-bspsrc-folder\bspsrc.jar" in Command Prompt (CMD).
• Java 8 (required in order to use BSPSource 1.4.3 or earlier)

References

References
1. "Application not launching caused by "java.lang.IllegalArgumentException: Comparison method violates its general contract!"". BSPSource. GitHub Issues.  Retrieved June 19, 2025.