In a Unity blog post today, Unity announced that Enlighten support was being removed from the Unity game engine. Enlighten is the lightmapping and global illumination solution used in Unity since Unity 5 was released. Enlighten was original developed by Geomerics, which was acquired by ARM technologies in 2013, then the technology was sold to Silicon Studio in 2017.
Details of the removal on the Unity blog:
Due to Geomerics shutting down Enlighten as a product, Unity is required to remove Enlighten.
Unity will continue support for Enlighten in the built-in renderer as it currently exists today (as-is, with no new platform support). The 2020 LTS will be the last version to contain Enlighten functionality for the built-in renderer, and it is fully removed in 2021.1.
Projects authored with HDRP Preview Enlighten functionality will continue to be supported as it currently exists today (as-is, with no new platform support) in 2019 LTS, with full removal of Enlighten functionality from HDRP in 2020.1.
They are working on a solution:
We are also fully committed to delivering a real-time GI replacement solution in 2021.1. The Unity team has a solid plan to solve this complex problem the right way, with great artists workflow and optimal runtime performance for 2021.1.
Additionally, in the linked forum discussion are some good details on the limitations of the current Enlighten solution that will be addressed in their new in-house solution:
Enlighten has had a good run for the money, some of the best looking titles have shipped using it. However, some of the underlying principles means that it is not a good fit moving forward.
Enlighten is largely surface based, requires a global pre-computation phase and is limited to diffuse transport with no real support for physically based non-opaque materials. Some of the drivers moving forward are:
- Fast iteration: Time-to-first-pixel needs to be fast, cannot have a lengthy pre-compute step.
- Easy authoring: We need to remove the dependency on authoring suitable UVs and other surface based authoring.
- Dynamic worlds: In addition to dynamic materials and lighting setup, we have to support dynamic geometry (eg. for procedural games).
- Unified lighting: The lighting container needs to be decoupled from surfaces. This allows all scene elements to use the same lighting including volumetrics and participating media.
- Large worlds: Due to the sheer size of levels today we need an easy way to to do localized light transport where what is lit and what is affecting that lighting is decoupled.
- Source access: We need to have full access to all source in-house. So that we can independently drive development forward, fix bugs and support future platforms. This is arguably the most important point.
For these reasons we have decided that the best course of action is to no longer pursue software we have limited control over and move on.
That said the feature set that is available now will be supported until 2023 (via 2020 LTS), and we are happy to support you in the transition.
I’m still not entirely certain what they mean by Geomerics shutting down however, as it’s resources were sold way back in 2017 and everything seems to be business as usual.