Full Spectrum Rendering in RPR for Blender

Full spectrum rendering (FSR) provides artists with a rendering framework that can be easily scaled from super-fast rasterized to fully accurate path traced, all with physically accurate materials and lighting.

FSR aims to fill the gap between the OpenGL viewports, like EEVEE, and full path-tracers, like Cycles. It uses Vulkan to achieve fast rendering with rasterization and to increase the rendering performance using the GPU. It also allows artists to add ray tracing effects for advanced viewport rendering, or switch to Vulkan-powered biased ray tracing or OpenCL full path tracing rendering modes.

FSR is meant to help artists to obtain a more interactive experience for viewport rendering and accelerate their work as much as possible, while maintaining physically correct lighting and shading. By switching between the FSR modes, users can easily balance the ray tracing visual quality against the rasterization performance based on their needs.

The Render Modes in Detail

FSR offers four render modes to support all stages of the rendering pipeline —from standard viewport creation to the final quality render.

Render Mode	Powered by	Runs on	Description
Low	Vulkan	GPU	High-performance rasterization mode for standard viewport creation. This is the fastest of all the modes, and is highly optimized for changes in geometry, material and lighting. Global Illumination effects will be less visible in this mode.
Medium	Vulkan	GPU	Hybrid mode for advanced viewport creation: rasterization with biased GI. This mode adds ray traced effects, such as reflection, refraction, ambient occlusion, etc.
High	Vulkan	GPU	Vulkan-powered ray tracing mode for look development and biased photorealistic rendering.
Full	OpenCL	CPU/GPU	OpenCL full path tracing mode, which is optimal for final quality renders, and for rendering complex scenes and materials.
Full (Experimental)	OpenCL	CPU/GPU	Windows only experimental version of the full path tracing mode for final quality renders. Partial support of features supported by the ‘Full’ mode.

Supported Hardware

Three of the four FSR modes run on top of Vulkan. Therefore, a Vulkan-compatible GPU is required.

Officially supported GPUs for Vulkan-powered FSR modes are:

• AMD Radeon™ PRO W6000 Series (Radeon PRO W6800, Radeon PRO W6600, and Radeon PRO W6600M)

• AMD Radeon Vega (Radeon Pro WX 9100, Radeon RX Vega 8/56/64/64 Liquid Cooled and subsequent models)

• AMD Radeon 2nd generation Vega (AMD Radeon VII and subsequent models)

• AMD Navi class cards (Radeon RX 5700 XT/RX 5700/RX 5000, Radeon Pro W5500, AMD FirePro W5000 and subsequent models)

• Limited support for Polaris cards Radeon RX 500 series as well as Radeon Pro WX 7100 and WX 3200

Apart from these, FSR may run on other GPUs that are not officially supported.

Note

If no GPU is detected on the system or the detected GPU does not support Vulkan-powered FSR modes, AMD Radeon ProRender will use its default Full OpenCL ray tracing mode, and the other FSR modes will not be available.

Supported Platforms

FSR is supported on the following operating systems:

• Windows 10

• Ubuntu

• macOS

Note

1. On Mac OS only the ‘Full’ mode is supported.

2. ‘Full (Experimental)’ mode is supported on Windows only.

Choosing Render Quality Mode

FSR modes are available in both the viewport and the final render. By choosing between the render quality modes, users can balance the visual quality of the output against performance based on their needs.

To switch between FSR modes, you can use the Render Quality options either in the Render Quality settings or in the viewport. Note that when an FSR mode is set in the viewport, this mode is also applied to the production render, and vice versa, once set in the Render Quality settings, the quality mode is applied to the viewport render preview.

Note

If FSR is not supported by your system, the Render Quality options will not be available in the viewport and in the render quality settings.

Choosing Render Quality in the Viewport

To switch between the FSR modes in the viewport, in the top left corner of the viewport click RPR > Render Quality and choose the required option.

Note

In the viewport, FSR is supported in both the Render Preview and Look Dev modes.

Download the above scene (.blend)

Choosing the Final Render Quality

To choose the render quality mode for the final render, in the Render Settings, expand the Quality panel and choose the necessary option in the Render Quality list.

Notes

There might be situations when you need to render the same scene on systems with different hardware configurations (like your work and home computers). In such cases, it is recommended to set the FSR mode to Full before you save your work and close the scene. Opening a scene with a preset FSR mode that is not supported on the system may cause errors in the scene.

Limitations

In terms of supported plug-in features, FSR Vulkan-powered modes are somewhat different to the OpenCL full path tracing mode. While the OpenCL path tracer supports all of the plug-in features, FSR modes that run on top of Vulkan have a set of limitations. These limitations are outlined below.

Quality

Render Quality can be controlled using the Total Ray Depth parameter.

Ray depth values for some specific surface types) as well as Ray Cast Epsilon, Clamp Radiance and Pixel Filters options are not supported.

Sampling

The only supported sampling mode is fixed sampling. Adaptive sampling is not supported.

Tiled rendering is not supported either.

Render Passes (AOVs)

Supported render passes are:

• Depth

• UV

• Object Index

• Material Index

• World Coordinate

• Shading Normal

• Diffuse Albedo

• Background

No other render passes are available in the UI when you switch to any of the FSR Vulkan-powered modes.

Viewport Render Modes

Render modes in the viewport are not supported.

Geometry Settings

The following geometry settings are not supported: shadow catcher, reflection catcher, visibility settings and displacement settings.

Lights

Since they are adapted for Vulkan-powered modes, some of the light sources and their parameters might look a bit different than in the OpenCL full path tracing mode.

Light group parameters are not supported.

Camera Effects

Motion blur and depth of field effects, as well as camera shift are not supported.

Denoiser

All denoiser filters are supported, except for the Machine Learning filter.

Note that FSR Low and Medium modes use denoising internally to speed up rendering, and yield little to no noise in the render output. The denoiser will mostly be required for the High FSR mode, as this mode might render noisy outputs.

Shading

The following nodes are not supported or only partially supported.

Node	Details
Ambient Occlusion	Not supported.
Blackbody	Only numeric inputs are supported.
Geometry	Only Position, Normal and Incoming modes are supported.
Normal Map	Space and UV map inputs are ignored.
RGB Curves	Supported with limitations.
Texture Coordinate	Only Normal and UV modes are supported. UV is used instead of Generated.
Principled Hair BSDF	Not supported.

Among other limitations are:

• Of all types of Texture category shader nodes, only the Checker, Noise and Image are supported.