Version: 2019.4
The Progressive Lightmapper
Lightmapping using Enlighten (deprecated)

The Progressive GPU Lightmapper (preview)

Note: This is a preview feature and is subject to change. If you have ScenesA 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
that use this feature, you might need to update them in a future release. Do not rely on this feature for full-scale production until it is officially released.

The Progressive GPU LightmapperA tool in Unity that bakes lightmaps according to the arrangement of lights and geometry in your scene. More info
See in Glossary
is a backend for Unity’s Progressive Lightmapper which uses your GPU and Dedicated Video RAM (VRAM) 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 Probes.

Hardware and software requirements

In order to use the Progressive GPU Lightmapper, your computer must meet these minimum specifications:

  • At least one GPU with OpenCL 1.2 support
  • At least 4 GB of dedicated GPU memory
  • A CPU that supports SSE4.1 instructions

If the Scene you are baking requires more VRAM than is available on the designated GPU, bake times can significantly increase. See Performance for information to help you reduce the time it takes to bake your Scene.

Performance

The specifications of the GPU you use to bake and the amount of VRAM dedicated to that GPU both influence your experience of the lightmapper’s performance. See Hardware and software requirements.

Other applications competing for GPU resources also have an impact on baking performance. Depending on your hardware vendor, reductions in the amount of VRAM available to Unity can slow down the bake, cause it to fail, or even result in the Lightmapper falling back to the CPU if the GPU cannot meet minimum memory requirements. Closing other applications while you are working with this functionality can improve stability and performance.

How to optimize your bake speed

There are several ways you can reduce bake times and avoid situations where bakes exceed the VRAM available to the GPU designated for baking.

  • Close other GPU-accelerated applications. GPU-accelerated 2D image editing and 3D modelling software uses VRAM. Turn off accelerated graphics functionality or quit these applications.

  • Switch to a CPU-based denoiser. GPU-based denoisers also use VRAM capacity. Switch to a CPU-based option, like Intel Open Image, which uses system RAM instead.

  • Use Light Probes for smaller GameObjectsThe fundamental object in Unity scenes, which can represent characters, props, scenery, cameras, waypoints, and more. A GameObject’s functionality is defined by the Components attached to it. More info
    See in Glossary
    . GameObjects such as debris or small props use up space in lightmaps but might not contribute significantly to the look of a scene. To optimize bake speed, disable Contribute Global Illumination for these GameObjects’ Mesh Renderers and light them with 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
    instead.

  • Designate separate GPUs for 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
    and baking. If your computer has more than one GPU, you can designate one for rendering and one for baking. See Configure GPU selection.

  • Use a lower number of Anti-aliasing samples. The default value for this setting in the Lightmap Parameters Asset is 8. When you increase it, Unity uses more VRAM. When you are using a lightmap size of 4096 or above, this can quickly exceed the memory of many consumer GPUs.

Configure GPU selection

If you have at least two GPUs, you can specify one GPU for rendering the Scene and another for baking lighting. This might be desirable in cases where there is insufficient VRAM available for the default GPU to both render your scene and bake it using the Progressive GPU Lightmapper.

To change which GPU Unity uses for baking:

  1. Open the Lighting window (menu: Window > Rendering > Lighting).
  2. Navigate to the Workflow Settings section.
  3. Use the GPU Baking Device drop-down menu to select a GPU.
The Progressive Lightmapper
Lightmapping using Enlighten (deprecated)