Graphics Rendering Technology Comes Full Circle: AMD Introduces Forward Rendering Path For Unreal (Updated)

Update, 3/1/2017, 5:00 p.m. PST: A representative from Epic Games informed us that AMD, in fact, did not create the forward render path for Unreal Engine 4.15. Epic Games built the forward rendering path. AMD simply revealed compatibility with it at the Capsaicin and Cream event.

During the AMD Capsaicin and Cream event, AMD announced that a graphics technology relic from days gone by is coming back to the forefront, and for a rather ironic reason—the benefit of the virtual reality industry. Epic created a forward rendering path for Unreal Engine 4.15, which is intended to improve rendering performance and help developers achieve the constant 90fps performance benchmark they seek for VR games.

Forward rendering isn’t a new technique. It was used in the early days of GPU rendering, but several years ago, the technique was supplanted by deferred rendering because it saves work by splitting the geometry and lighting work into to separate passes instead of rendering everything at once.

The deferred rendering technique is helpful to improve lighting in a scene, but it is incompatible with post-processing anti-aliasing techniques. It also comes at a per-frame performance cost and high memory usage. Thus the advanced lighting features, such as screen-space reflections, that deferred rendering brings to the table are untenable for VR applications.

Forward rendering doesn’t offer as many fancy bells and whistles as deferred rendering, but it delivers where it counts. Forward rendering is a simpler and lighter weight process that the GPU can handle faster than deferred rendering, and therefore offers higher rendering performance (AMD claimed it offers a 30% improvement). Forward rendering is also compatible with multi-sample anti-aliasing technology, which is of great benefit to VR experiences, because smoothness is of great importance hen you’re up close and personal with a screen.

AMD is already working with a handful of developers to explore the benefits of its forward rendering path for Unreal Engine. Epic Games is exploring those benefits with Robo Recall; First Contact Entertainment is implementing forward rendering into its upcoming expansion for ROM: Extraction, called Overrun; Limitless Studios is putting forward rendering to use in a new title it’s building, called Reaping Rewards; and Survios (creator of Raw Data) announced a new game called Sprint Vector that leverages AMD’s new old technology.

“AMD has been on a continuous mission to make VR accessible to as many people as possible, and the forward rendering path in Unreal Engine 4 is a big step in that journey,” said Raja Koduri, Senior Vice President and Chief Architect, Radeon Technologies Group, AMD. “Anyone who has experienced Epic’s Robo Recall will immediately attest to the benefit of forward rendering in VR. We are working with VR developers to explore the benefits of forward rendering, which can result in beautiful, high-performing games on Radeon graphics.”

 Kevin Carbotte is a contributing writer for Tom's Hardware who primarily covers VR and AR hardware. He has been writing for us for more than four years. 

  • coolitic
    Umm, isn't deferred ONLY compatible with post-process and temporal AA?
  • Dosflores
    Good old forward rendering and MSAA are great for VR. Even the greatest graphics look terrible on a HMD when there isn't any AA method implemented. Of course, you only have to stand that on mobile and PlayStation VR, but fortunately Unreal Engine 4 excels in both.