Games Focus: Rendering that scales with your needs

This is the second blog in our Games Focus series, which highlights key product development initiatives for the year ahead and beyond. In this post, we cover the status, upcoming release plans, and future vision for our scriptable render pipelines.

As Ralph wrote in his blog last week, our mission is that Unity enables you to create extraordinary games of all kinds and reach your players wherever they are. We launched this series of posts to clarify what features and improvements we’re prioritizing throughout next year and into 2024 and 2025.

My name is Ali Mohebali, and I’m a product manager for graphics at Unity. I started my journey in the video game industry as an engineer 19 years ago and have had the honor of working at Unity for the last three years. This post is a collaborative effort between myself and my colleagues Aljosha Demeulemeester, director of graphics engineering, and my fellow product managers for graphics, Mathieu Muller and Steven Kent.

Our post today is about how we’re continuing to improve the Universal Render Pipeline (URP) and High Definition Render Pipeline (HDRP) to help you create scalable graphics across all the platforms Unity supports. Let’s take a look at what’s available for you today with each of the rendering pipelines, then at what’s planned in 2023 and beyond.

With the ever-changing fragmentation in hardware capabilities, it’s complex and time-consuming to test, optimize, and scale your visual content to help it reach as broad an audience as possible. Our aim with the Scriptable Render Pipelines (SRPs) is to reduce the cost for you to scale and deliver your games for the widest platform reach, with the best possible visual quality and performance.

We strive to provide state-of-the-art, physically correct rendering out of the box, and, for those creators that require it, also offer extensible rendering for heavy stylization, deep optimization, and rapid prototyping. Additionally, we want the source code of our render pipelines to be readable, modifiable, and written in productive C#, thereby giving you the option for deeper customizations when you need it.

To reach our goal, we provide the Universal Render Pipeline and the High Definition Render Pipeline, two specialized SRPs that serve different purposes. Let’s look at the progress we’ve made with each SRP, then at our longer-term goals for rendering in Unity.

We have designed URP to be efficient for you to learn, customize, and scale to all Unity-supported platforms. Our top goal is that URP is the leading renderer for mobile, XR, and untethered hardware.

URP is the successor to our Built-in Render Pipeline. Our graphics team is working to ensure it will provide all the functionality you are familiar with, but with better performance, greater customizability, and more productive workflows.

Ralph has already mentioned some of the significant strides we made with URP in the 2021 LTS release, which moved its functionality closer to that of the Built-in Render Pipeline.

A number of 2021 LTS improvements we’re personally excited about include:

• Point Light Shadows
• Deferred Rendering Support
• Decals
• Enlighten Realtime Global Illumination
• Light Cookies
• Reflection Probe Blending
• Reflection Probe Box Projection
• Lens Flare

We also improved our workflows for customizing URP and managing its performance, including Shader Graph Surface Options, Depth Pre-pass support, Light Layers, Volume System Update Frequency, and the Render Pipeline Debug Window.

In the 2022 Tech Stream releases so far, we’ve made further improvements to workflows and performance based on your feedback. Some highlights that are now in beta include LOD Crossfade, Rendering Decal Layers, Full Screen Shader Graph support, and a more intuitive workflow for custom post-processing.

In 2022.2, we also added the support of Forward+, which offers the advantages of the Forward rendering path while eliminating the light limit count.

A small but impactful improvement in 2022 is our focus on the SRP core APIs that unlock several important use cases accessible in the Built-in Render Pipeline. For example, the functionality exposed by Camera.Render that allows you to trigger rendering outside the standard update loop is now available via RenderPipeline.SubmitRenderRequest API. The Override Shader concept added to the DrawingSettings can be used to achieve the same functionality as the Built-in Render Pipeline’s Camera.SetReplacementShader.

With the 2022.2 release, URP provides the majority of the functionality offered by the Built-in Render Pipeline, and in certain areas exceeds its quality and performance. If you are looking to make the move to URP, we recommend you compare the functionality between the two pipelines to help with your decision, and download our new advanced e-book for detailed, step-by-step information to make the change.

We’re really excited to see the launch of more and more games using URP, including amazing titles such as Lost in Random, Two Point Campus, Circuit Superstars, Neon White, Crash Bandicoot: On the Run!, and LEGO Builder’s Journey.

Our goals for URP in the 2023 releases are to finalize remaining items for functional parity with the Built-in Render Pipeline, provide better documentation and guidelines, and polish the workflows and performance based on your feedback. Next to Volume framework performance, shader build time, and memory usage improvements, some new feature highlights we’re working on are Adaptive Probe Volumes, Temporal Anti-Aliasing, High Dynamic Range Display Output, and Foveated Rendering for VR.

One of your most requested items is Surface Shader functionality. In the coming weeks, we will share an update and public demo on Block Shaders with a new intuitive syntax and unified shader authoring workflow across the rendering pipelines.

We are also making further improvements to the foundation of URP, mainly via the ongoing project of adopting Render Graph in URP. This will allow us to increase the stability of URP on all platforms. At the same time, Render Graph guarantees that a minimal amount of GPU memory is used. Render Graph will be available in 2023. The adoption of Render Graph also allows us to bring the code base closer to HDRP to prepare for additional compatibility between the two pipelines as part of our longer-term goal for SRPs.

With full functional parity, you’ll be able to confidently use URP instead of the Built-in Render Pipeline without needing to compare features. This will greatly simplify decision making when selecting a render pipeline for your game. We want to give ample time for you to migrate your projects, so we will still provide full support for the built-in option in 2023 LTS.

Resources

If you’re looking to take the step from using the Built-in Render Pipeline to URP, we recommend our new technical guide, Introduction to the Universal Render Pipeline for advanced Unity creators, which my team and I worked on.

We have seen some amazing productions use HDRP over the past three years, such as Hardspace: Shipbreaker, Recompile, I Am Fish, Disciples: Liberation or Syberia: The World Before, which is even running 4K on the Steam Deck.

In this same period, we received great feedback from developers and artists that led to improvements for extensibility, the UX for using physical lights, and better performance and stability. We also introduced innovative features and technologies like NVIDIA DLSS, AMD FSR, Volumetric Clouds and ray tracing.

Today, using an LTS version of HDRP, a team like Light Brick Studios has access to a complete set of scalable features working together coherently, enabling them to upgrade the award-winning mobile game LEGO Builder’s Journey to a realistically rendered game for PC. And a team like Stunlock Studios can leverage the combination of Unity’s extensibility, DOTS, and HDRP’s advanced rendering technologies to power their large-scale multiplayer game V Rising. Just like animated films using physically based lighting don’t always need to look photorealistic (think Spiderman: Into the Spider-verse or our own short film WiNDUP), HDRP can also power stylized games like Slime Rancher 2.

2022.2 will bring full support for using Shader Graph with HDRP, providing you with the option to use it to create custom post-processing passes, Custom Render Textures, and Local Volumetric Fog.

Environment artists can efficiently push visual quality with the new Water System (check the forum here), better lighting of cloud layers, and improved Volumetric Clouds, allowing you to blend between two weather conditions.

Finally, to make high-fidelity trailers and cinematics, character and lighting artists can access the high-quality eye caustics and area light shadows used in the Unity demo Enemies, and the Pathtracer can render faster noise-free images using NVIDIA Optix™ AI accelerated denoiser or Intel® Open Image Denoise.

Optimizing performance is always our first priority, especially for CPU usage where we know your games can experience limitations. For features, we will continue to leverage more of the research coming from our colleagues who have brought many innovations powering Unity and the CG industry, and work with the Wētā Digital, Ziva, and SpeedTree teams from our art tools portfolio to focus on specific areas and innovations which are key to PC and console games.

Some of these areas include:

• Environment: Make it easier to render and light high-definition environments under changing weather and time conditions, including improvements to Adaptive Probe Volumes, Capsule Shadows, and much more.

• Characters and creatures: Enable high visual fidelity rendering of playable and non-player creatures and characters. You can see a glimpse of that future in our Lion and Enemies demos, as well as in this short introduction to the experimental strand-based Hair Solution.

Resources

New technologies means learning new workflows and tools. We recommend checking out video tutorials on physical light intensities and cameras lenses and exposure, or doc materials and blog posts like these ones on Volume systems and Scalability Settings.

But for many creators these will be new concepts to learn – for a broad view that touches on many aspects of HDRP, check out The definitive guide to lighting in the High Definition Render Pipeline (HDRP).

Our solution for performant, scalable rendering started with two specialized render pipelines that serve different purposes.

URP offers optimal visual quality on mobile devices and runs on every platform that Unity supports. It provides maximum extensibility for stylized visuals and optimizations that are not physically correct.

HDRP provides the best possible visual quality that’s only possible on high-end platforms. It offers a tightly integrated feature set that provides physically correct lighting across these features.

The next step towards fully scalable rendering is to facilitate the use of both URP and HDRP for a single game. Such a game requires both the quality that HDRP offers on the high end and the wide platform reach of URP. LEGO Builder’s Journey and Road 96 are amazing games that target PC and console with HDRP and mobile and untethered hardware with URP. We want to enable more Unity creators to reach the same level of content scalability.

Since the Editor is designed to use one pipeline per project, to achieve this today requires you to set up two projects, one with URP and the other with HDRP, and to reauthor the content. The end goal is to be able to select the pipeline that offers the best fit for your game for each platform with minimal reauthoring to increase your productivity. This allows you to have optimal quality and performance on each platform.

We are working on two components to reach our goal.

First, we are modifying the Editor so you will be able to include URP and HDRP in the same project. Different scenes in your project will be able to use a different render pipeline. With Render Pipeline Coexistence, you can author and maintain different visual assets tailored to each pipeline in a single project and build and run the content for a target platform with a specific rendering pipeline and its associated assets. We made good progress in this area and will share more detailed information on this soon.

Second, we are increasing the compatibility between URP and HDRP so less work is required to reauthor content to render a scene with different render pipelines. We have already started in the past two years to bring more feature parity and compatibility between HDRP and URP (SRP lens flares, terrain details and trees, VFX Graph, Shader Graph Master Stack and Full Screen Master Node, Rendering Layers, Rendering Debugger). We’ll investigate shared data models for materials, lights, cameras, and post-processing so that the content will be understood by all rendering backends that Unity supports with minimal reauthoring. For example, Unity 2023 will include a cross pipeline Shader Graph based standard material for Lit and Unlit that is compatible with both pipelines.

We hope you’ll stay engaged with our Games Focus series by posting your questions and comments for this post in our forum. 

Visit our rendering and visual effects roadmap for more details about what we’re working on. You’ll need to log in with your Unity ID and accept to use functional cookies. Each card on this interactive page is clickable, giving you more details about each topic while providing you with the option to share your feedback. Click on a card, select the level of importance of the topic to you, add your point of view, and submit. This feedback is then routed to the proper product teams.

Keep your eyes out for more updates in this series, and share your feedback on the forums.