In Unity 2018, Unity released a new programmable graphic pipeline. Alongside this release they implemented two pipelines, the new HD pipeline and the Lightweight Render Pipeline(LWRP). Today they released a new version of the LWRP, 4.0.0 preview. If you are using the existing lightweight pipeline in your project be sure to pay close attention as there are code breaking changes in this release. This release includes a switch to physically based lighting that will see lighting reduced from three render passes to one. The forward renderer in the LWRP also has the ability to reduce draw calls by half.
Details of the new pipeline from the Unity blog:
This version changes the light attenuation computation to be physically based. This change means that you don’t have to increase the range of your light to control the attenuation. Instead, you should control the attenuation with the light intensity. Baked GI has changed to match the realtime attenuation. When you upgrade to LWRP 4.0.0-preview, it is likely that you have to upgrade your light settings as well.
We are pushing work to have LWRP out of preview as soon as possible. Therefore for this version, we focused most of our time in API design to implement much feedback we received over the past months and evolve both our C# and shader API to be more easy to use, extensible and flexible.
This version introduces API breaking changes. Breaking changes are the reason we bumped the major version number. If you didn’t fork LWRP or authored custom shaders without using ShaderGraph, upgrading your shaders to this version requires some work. We apologize for the nuisance, but this is required so we can evolve. Once out of preview, there won’t be any more breaking changes.
Please check the changelog to help you upgrade shaders to version 4.0.0-preview and reach out in this thread with upgrading issues so we can help you.
Be sure to watch the following video for details on how to install and configure the 4.0.0 preview LWRP.