Hammer++
Hammer++ is a free Windows modification of Valve’s Hammer editor for building maps in the Source engine.
What Hammer++ is
Hammer++ is a free Windows modification of Valve’s Hammer editor for building maps in the Source engine. Its stated aim is to make the editor more stable and current through fixes and improvements. It can simulate Source lighting within the editor, with adjustable quality and speed and dynamic updates, and preview particles, fog, skyboxes, rope physics, render effects, and material proxies. Mapping tools include a 3D gizmo, polygon and sprinkle tools, multiple cordons, brush merging, and placing objects on floors or ceilings. If the editor crashes, it shows a detailed error and autosaves open VMF files. Saved VMFs retain precise vertex data while also including less precise data for compilers and compatibility with other Hammer versions. Downloads bundle HLMV++, which users may optionally install. The maker directs users to its official Discord for discussion and says the project is not affiliated with Valve. The download page lists build 8871, last updated April 14, 2026. The maker also notes antivirus software may flag downloads and advises allowing them or adding an exception.
Good
- Simulates Source lighting with adjustable quality and speed.
- Previews particles, fog, skyboxes, and render effects.
- Autosaves open VMF files after a crash.
- Provides tools for polygon work, brush merging, and placement.
- Download includes optional HLMV++.
Watch out
- Available for Windows only.
- The old Source 2013 Multiplayer version is unsupported.
- CS:GO support is frozen on build 8864.
- Antivirus software sometimes flags downloads.
Who it suits
Hammer++ suits Windows users who create Source engine maps and want editor-based lighting and visual previews alongside mapping tools. It is not suited to users relying on the old Source 2013 Multiplayer version; CS:GO support is frozen on build 8864.
Verdict
Hammer++ offers Source-focused previews and mapping tools, with crash recovery that autosaves open VMFs. Check the stated game-version limits and be aware the maker reports occasional antivirus flags.
Plans and prices
From Hammer++'s own pricing page, checked 15 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Hammer++ | Free | Source-engine level editing · branch-specific builds · Windows download |
The facts
Each one read from Hammer++'s own pages, with the date it was checked.
What it does
- Antivirus issue
- The maker says downloads are sometimes marked as malware by antivirus software and advises allowing them or adding an exception.checked 28 Sep 2026
- Branch compatibility
- Separate downloads exist for different Source branches, and the site warns that choosing the wrong branch prevents startup.checked 15 Oct 2026
- Bundled companion
- HLMV++, a model viewer, is bundled with downloads but is optional to install.checked 15 Oct 2026
- Compatibility limits
- The page says the old Source 2013 Multiplayer version is unsupported and CS:GO support is frozen on build 8864.checked 28 Sep 2026
- Compile workflow
- Compilation runs in a separate command window so the editor no longer freezes during compiling.checked 15 Oct 2026
- Crash recovery
- If Hammer++ crashes, it displays a detailed error message and autosaves open VMF files.checked 28 Sep 2026
- Current build
- The download page lists build 8872, last updated October 1, 2026.checked 15 Oct 2026
- Download status
- The download page lists build 8871, last updated April 14, 2026.checked 28 Sep 2026
- Editing tools
- It adds a 3D gizmo, adjustable pivot, polygon and sprinkle tools, real-time vertex editing, three-point clipping, brush merging and surface movement tools.checked 15 Oct 2026
- File compatibility
- Hammer++ saves precise vertex data in VMF files while also saving imprecise data for compilers and compatibility with other Hammer versions.checked 28 Sep 2026
- GPU requirements
- VRAD++ GPU acceleration requires at least an Nvidia RTX 2000-series, AMD RX 6000-series or Radeon 680M+, or Intel Arc A-series GPU with Vulkan 1.3 drivers.checked 15 Oct 2026
- Independent complaint: camera controls
- A Mapcore reviewer reported that arrow keys could not rotate the 3D camera as in vanilla Hammer.checked 15 Oct 2026
- Independent complaint: missing asset filters
- A Mapcore reviewer missed a used-assets-only filter and model usage counts in the model browser.checked 15 Oct 2026
- Independent complaint: texture scaling
- A Mapcore user found that stretching brushes also stretched their textures, requiring frequent face-edit adjustments until texture lock was discovered.checked 15 Oct 2026
- Independent popularity claim
- A Steam Community overview described Hammer++ as making Source level creation significantly faster and demonstrated model, skybox, particle, fog, rope, gizmo and lighting features.checked 15 Oct 2026
- Independent praise: lighting
- Mapcore users repeatedly praised the lighting preview as useful for making lighting changes without compiling and liked the skybox preview.checked 15 Oct 2026
- Independent praise: modern manipulation
- Mapcore reviewers highlighted the 3D gizmo for translating, rotating and resizing objects and welcomed the broader quality-of-life improvements.checked 15 Oct 2026
- Independent product description
- BSPMarket describes Hammer++ as a free ficool2-developed Valve Hammer extension with separate builds for Garry’s Mod, Team Fortress 2 and Portal 2.checked 15 Oct 2026
- Independent setup guidance
- Momentum Mod documentation recommends the Garry’s Mod build as easier to configure and says the CS:GO setup needs more tools and disk space.checked 15 Oct 2026
- Independent setup limit
- Momentum Mod’s CS:GO setup guide estimates about 32 GB of disk space depending on mounted games.checked 15 Oct 2026
- Installation
- Installation instructions are supplied in README.txt inside each download, and updates are installed by overwriting the existing files.checked 15 Oct 2026
- Integrations
- The download page says HLMV++ is bundled with downloads and can be optionally installed.checked 28 Sep 2026
- Keybinding limitation
- The keybind editor cannot assign mouse bindings, and modifier keys may not work for every binding.checked 15 Oct 2026
Where it runs
- Independent Linux experience
- A Reddit Linux guide reports Hammer++ can run through Proton, with working lighting, compilation, custom assets, logic and 3D view, but buggy and laggy 2D and texture-browser interfaces.checked 15 Oct 2026
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