PTBake

Path-traced lighting for Source maps.

Replaces VRAD in Hammer or Hammer++, using your GPU to bake lighting.

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Windows x64

Abstract light study: a light installation in a shallow gallery alcove, with a warm vertical light bar, a cool overhead bar and a low plinth. Website artwork, not PTBake output.

Results

No bake captures are published yet.

Get the beta.

Public beta · Windows x64

One Windows executable with nothing to install. Choose it as Hammer's lighting compiler and compile as usual.

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Requirements

System: Windows, 64-bit
Minimum GPU: Supports Vulkan 1.0
Recommended: GPU with hardware ray tracingOptional. NVIDIA RTX, AMD Radeon RX 6000 or newer, Intel Arc.

Beta notes

ptbake.exe is not code-signed.
The first bake may take longer, including after a graphics driver update.
Heavy maps on slower or laptop GPUs can trigger a Windows GPU reset. The bake stops and writes a crash report.

Setup

Set up in Hammer or Hammer++

Choose PTBake as your lighting compiler, then compile maps through Hammer as usual.

Download and extract PTBake. Place ptbake.exe in the same folder as hammer.exe or hammerplusplus.exe. That is usually your game's bin folder, but some installs keep the editor in a subfolder of bin: use the folder your editor actually runs from.
Open Hammer or Hammer++. Go to Tools > Options.
Select the Build Programs tab. If you have more than one game configuration, choose the one you want to use with PTBake.
Change the RAD executable. Click Browse beside that field and select the ptbake.exe you extracted. This replaces the path to your current lighting compiler.
Save your settings. Click Apply, then OK.
Compile your map as usual. Keep the lighting (RAD) step enabled. Hammer will use PTBake to bake the lighting.

Keep your original lighting executable. To switch back, select it again in the RAD executable field.

Command-line usage

Open a terminal in the folder with ptbake.exe and check the build:
```
ptbake.exe -version
```
It prints the version, source commit, build id and shader set. Include this in bug reports.
Bake a compiled map in place:
```
ptbake.exe -game <gamedir> <map.bsp>
```
<gamedir> is the mod folder that holds gameinfo.txt, for example ...\Half-Life 2\hl2. The lit map replaces the input .bsp; add -output PATH to write it elsewhere.

Quality presets

Preset	Samples	Bounces	Blur	Use
`-fast`	64	4	2	Quick preview
`(none)`	1024	20	1	Default
`-final`	4096	20	1	Release bake

-samples, -bounces and -blur override a preset. More samples mean less noise and a longer bake. In Hammer, add a preset to the RAD step's parameters (Run Map, Expert mode).

Advanced options

-bounces N sets how many times light bounces between surfaces. The default is 20.
-rad bakes area lights from .rad texture lights. Experimental and off by default.
-adaptive turns on adaptive sampling. Experimental.

In Hammer, add them to the RAD step's parameters (Run Map, Expert mode).

It takes the VRAD step.

PTBake is a command-line compiler. It reads a compiled .bsp, bakes its lightmaps, prop lighting and ambient lighting on the GPU, and writes them back. The rest of your compile stays the same.

01
Compile as usual
Your geometry and visibility steps run as before. PTBake replaces only the VRAD step, in Hammer or in a build script.
02
Bake on the GPU
PTBake loads the map with the materials and models from the game folder you pass with -game, traces its lighting, and writes it back into the same .bsp.
03
Test in game
Hammer's Copy File step copies the lit map into the game, the same as after VRAD.

What it handles

Bounced light: Light reflects between surfaces, carrying their color into the surrounding scene.
Light from the sky: The sky texture contributes light and color to the scene.
Your existing lights: Supports light, light_spot, light_environment and light_directional. Named and switchable lights can still toggle in game. Set _light_radius for softer shadows.
Static prop lighting: Bakes lighting onto static props, with per-texel lightmaps for props using generatelightmaps in Garry's Mod and Source MP maps.
3D skyboxes: Sunlight, skylight and bounced light travel between your map and its 3D skybox.
Glass, foliage and water: Accounts for glass, water and cutout textures such as foliage when baking shadows and bounced light.
Ray tracing hardware is optional: Uses hardware ray tracing when available. GPUs without it can still bake using software tracing on the GPU.
LDR and HDR: Bake LDR, HDR or both. With -both, PTBake shares data between the two lighting modes to keep BSP size down.

Report a problem.

Beta reports shape the next build. Tell us what went wrong; logs help when you have them.

The feedback link for the beta is not published yet.

What to include

What happenedWhat went wrong, what you expected, and the steps to reproduce it. Screenshots help with lighting problems.
Your PTBake versionThe first line of Hammer's compile window shows it.
Logs, if you have themThe compile log, and the crash report if the bake stopped with an error.

Save the compile log from Hammer

Copy the output from Hammer's compile window into a text file and attach it.

For a more detailed log:

Open Run Map and switch to Expert mode.
Select the lighting (RAD) step.
Add -log-file and a path to a new file to its Parameters, for example -log-file C:\maps\mymap-ptbake.log.
Compile again, then attach that file.

Use a file name that doesn't exist yet: PTBake won't overwrite a file.

Find the crash report

When a bake stops with FATAL GPU ERROR, PTBake writes a file named after your map, such as mymap.ptbake-crash.txt, next to the compiled map. From Hammer, that is usually the folder with your .vmf. Attach it as it is.

From the command line

ptbake.exe -version prints the version, source commit, build id and shader set. Add -log-file PATH to a bake to save the detailed log.

If a bake stops with a GPU error

Close games and other GPU-heavy programs.
On a laptop, connect AC power.
Update the graphics driver, then reboot.
If it still fails, add -no-ray-query to the RAD step's parameters to use software ray tracing instead, and mention it in your report.