Assembly is a manager for the files embedded inside a compiled Source Engine map (.bsp). Every BSP contains a "pakfile", a zip archive of custom content (materials, models, sounds, scripts) that ships with the map. Assembly lets you browse that archive like a file explorer, add and remove files, and run an asset scanner that finds content your map references but does not embed.

Loading a Map

You can open Assembly from the dashboard, or open a specific map directly from Hammer > Map Tools > Actions > Load in Assembly.

Load a .bsp by either:

• Dragging and dropping the file onto the window,
• Clicking Choose file (or File > Open), or
• Arriving from Hammer's Map Tools with the map preloaded.

Assembly shows the map's embedded files as a folder tree. Well-known Source Engine file types get distinct icons (VTF/VMT materials, MDL models, audio, nav files and so on), and file sizes are shown throughout.

Browsing and Editing the Pakfile

With a file or folder selected you can:

• Preview: Common file types can be previewed in place, including VTF and DDS textures and MDL models.
• Add files from disk: Embed new files into the current folder.
• New folder: Create a folder in the tree.
• Download: Extract a file out of the pakfile to disk.
• Remove: Delete the selected file or folder from the pakfile (asks for confirmation).

The Edit and View menus expose the same operations plus the asset report.

The Asset Scanner

Open the asset report from the View menu to scan the map for every material and model it references, covering brush materials, static props and entity keyvalues, including each material's textures and each model's companion files. Every referenced asset is given a status:

• Embedded: Already inside the map's pakfile. Nothing to do.
• Stock: Ships with the game itself.
• Loose: Only exists as a loose file in your local game installation. Other players will not have it; this is content you should embed.
• Missing: Referenced by the map but not found anywhere.

When your game installation is mounted, you can fix problems directly from the report:

• Embed (per row): Copies that file from your game installation into the pakfile.
• Embed all loose files: Packs every loose asset in one click.

Saving

Use File > Save to write your changes back. The .bsp is updated in place, and embedded files are stored uncompressed, which is valid for all Source Engine builds.

Exiting

Use the exit action to return to the dashboard. You will be asked to confirm, as any unsaved pakfile changes are lost when you leave.