Version: 2018.4
Progressive CPU Lightmapper

Progressive GPU Lightmapper (Preview)

Note: This is a preview feature and is subject to change. Any Scenes that use this feature may need updating in a future release. Do not rely on this feature for full-scale production until it is officially released.

The GPU Lightmapper gives you an interactive workflow when you’re setting up and tweaking the lighting in your sceneA Scene contains the environments and menus of your game. Think of each unique Scene file as a unique level. In each Scene, you place your environments, obstacles, and decorations, essentially designing and building your game in pieces. More info
See in Glossary
. Because this lightmapper uses the GPU in your computer to generate baked lightmapsA pre-rendered texture that contains the effects of light sources on static objects in the scene. Lightmaps are overlaid on top of scene geometry to create the effect of lighting. More info
See in Glossary
and Light probesLight probes store information about how light passes through space in your scene. A collection of light probes arranged within a given space can improve lighting on moving objects and static LOD scenery within that space. More info
See in Glossary
, it’s a faster alternative to the CPU Progressive Lightmapper. Sampling and noise patterns look slightly different than those produced by the CPU lightmapper, because the sampling algorithm is different.

Hardware and software requirements

To use the Progressive GPU Lightmapper, your computer must have:

  • A Windows operating system
  • At least one GPU with OpenCL 1.2 support
  • At least 2GB of dedicated GPU memory
  • CPU that supports SSE4.1 instructions

If your computer has more than one GPU, Unity automatically selects one for rendering and a different one for light baking. To change this, see: configuring which GPU to use for the lightmapper.

Note: If your project uses multiple Light Probe Groups, the Progressive GPU Lightmapper (preview) might use more than the available GPU memory and fall back to the CPU Lightmapper. Avoid using Progressive GPU Lightmapper (preview) with multiple Light Probe Groups.
To reduce GPU memory usage, put all Light Probes into a single Light Probe Group.

Note: If the baking process uses more than the available GPU memory, the process can fall back to the CPU Lightmapper. Some drivers with virtual memory support swap to CPU memory instead, which makes the baking process slower.

Selecting the Progressive GPU Lightmapper

To select the Progressive GPU Lightmapper in the Unity Editor: In your Project, go to Window > RenderingThe process of drawing graphics to the screen (or to a render texture). By default, the main camera in Unity renders its view to the screen. More info
See in Glossary
> Lighting Settings. Under Lightmapping Settings, find the LightmapperA tool in Unity that bakes lightmaps according to the arrangement of lights and geometry in your scene. More info
See in Glossary
property, and select Progressive GPU (Preview) in the drop-down menu.

Select the Progressive GPU Lightmapper under Lightmapper in Lightmapping Settings.
Select the Progressive GPU Lightmapper under Lightmapper in Lightmapping Settings.

Configuring which GPU to use

If your computer has more than one GPU, Unity automatically uses one GPU for rendering the Scene and the other GPU for baking lightmaps. If the GPU assignments don’t fit your needs, you can specify which graphics card to use for baking.

To see which GPU Unity currently uses for baking:

  • In the Editor, open the Lighting window. Next to Bake Performance, you can see the GPU.

To see the available GPUs in your machine:

  1. Make sure you’ve selected the Progressive GPU lightmapper in the Editor.
  2. Generate the lighting in your Scene.
  3. Open File Explorer, and navigate to the following path: C:\Users\USER\AppData\Local\Unity\Editor.
  4. Open the file called Editor.log.
  5. In the file, search for the line Listing OpenCL platforms. This should jump to the part of the log with information about OpenCL devices. Here, you can see your available GPUs along with their corresponding platform and device indexes.

To select a specific GPU for baking:

  • At the Command Line, enter this command (replacing platform and device index with the relevant numbers):

Unity.exe "-OpenCL-PlatformAndDeviceIndices" <platform> <device index>

Your choice of assignment should depend on your needs while you’re working on the Scene. If you assign the strongest GPU to either activity, this can incur a cost on the other activity. If you encounter issues, try re-assigning GPUs.


The Progressive GPU Lightmapper does not support:

  • Double-sided global illumination. The Lightmapper views all geometry as single-sided.
  • Casting shadows. Meshes always cast and receive shadows, regardless of your choice in Cast Shadows and Receive Shadows.
  • Baked LODA system for building multiplayer capabilities for Unity games. It is built on top of the lower level transport real-time communication layer, and handles many of the common tasks that are required for multiplayer games. More info
    See in Glossary
  • A-Trous filtering. It only uses Gaussian filtering.
  • The custom bake API (experimental)
  • Submeshes. The lightmapper uses material properties on the first submesh.

  • 2018–11–26 Page published
  • Preview of Progressive GPU Lightmapper added in 2018.3 NewIn2018X
Progressive CPU Lightmapper
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