Chapter 3: Emissive materials not rendering
Figure 5. The plane in the ceiling and the sphere both have emissive materials applied to them (left). Bloom enabled as a post processing effect to give an impression of a glowing material (center). Emissive plane and sphere both marked as GI contributors influencing lighting in the scene (right).
3.1 Why does this happen?
There are two types of issues related to emissive material rendering:
- Emissive materials do not appear as “glowing”. This indicates a post-processing issue.
- Emissive materials not contributing to global illumination. This indicates an issue with object or material setup.
3.2 How to fix it?
3.2.1 Enable bloom in the post processing stack
To create an impression of a glowing material, enable Bloom in the post processing stack of your choice. Refer to Built-in RP, URP, and HDRP documentation on how to do this.
3.2.2 Check material properties
Figure 6. Material inspector in the Built-in render pipeline. We highlighted Emission properties in blue.
If you intend on using emissive objects for lightmapping, make sure that:
- You have marked the GameObject in question as a GI Contributor. Due to the self-illuminating nature of emissive objects, you can set their Receive Global Illumination property to Light Probes. This will save space in the lightmap atlas.
- Global Illumination property is set to Baked in the Material Inspector. This property is available under the Emission input. Refer to Built-in RP, URP, and HDRP documentation for more details.
3.2.3 Inspect lighting settings
In the Lighting window, make sure that the Indirect Intensity property is not set to zero. Setting it to zero will disable all indirect lighting, including baked contribution from baked emissive objects.