Lightmapping

Note: currently, the lightmapping does not support Apple M1 (Silicon) architecture devices, and is expected to be supported in v3.1.

The baking system is the process of finally generating light maps and applying them in the scene by calculating the influence of all light sources on the object in the engine scene. The purpose of this system is to reduce the calculation of real-time light sources, thereby improving the efficiency of the scene.

Lightmap panel

The baking process is to calculate the generated results according to the parameters set on the panel, as shown below:

lightmap

The following table describes the specific meaning of each parameter:

ParameterDescription
MSAAMultisampling. Has the following values: 1, 2, 4, 8
ResolutionBaking map size. Has the following values: 128, 256, 512, 1024, 2048
GammaGamma correction value
GIScaleGlobal illumination scaling factor
GISamplesGlobal illumination sampling coefficient
AOLevelAO Level
AOStrengthAO Strength
AORadiusAO Radius
AOColorAO Color

Baking the lightmaps

The following three steps are required to turn on the baking system:

  1. Click the menu button in the top menu bar Project, click the Lightmap button in the pop-up menu bar to pop up the Lightmap panel.

    create lightmap

  2. Before baking, you need to set bakeable to true in the static light attribute of the light source component in the editor.

    Note: currently only one main direction light source is supported.

    enable lightbake

    • EditorOnly: When checked, only takes effect in the editor
    • Bakeable: When checked, enable bake static lighting
    • CastShadow: When checked, enable cast static shadow

  3. Set the lightmap properties of the MeshRenderer component.

    model lighting map settings

    • Bakeable: When checked, enable bake lighting
    • CastShadow: When checked, enable cast static shadow
    • ReceiveShadow: When checked, enable receive static shadow
    • LightmapSize: Lightmap size of the model

  4. In the lightmap panel that pops up, after setting the corresponding parameters, click the Lightmap Generate button and select the corresponding storage folder to generate the lightmap.

    Note: the storage folder must be under assets.

    create lightmap asset

Using

During the process of generating baked maps, there will be a generated progress prompt. After the generation, you can view it in the Baked tab in the lightmap panel.

bake result

  • Baked result (baked result display panel) shows the lightmap texture after baking, format is RGBE8.
  • Lightmap clear (clear button) can delete the generated result of baking
  • information output panel shows the information of each baked image (file name, size, etc.).

Notes:

  1. when artists create model resources, they need to include an additional set of UV for the lightmapping, in addition to the UV for the model itself.

  2. The model’s material needs to enable the USE LIGHTMAP rendering option:

    materials use lightmap