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Scene Optimization

This topic covers best practices when configuring scenes within an Unreal Engine project for use with RenderStream.

Here are several useful tips and best practices for optimizing your Unreal Engine scenes for use with RenderStream.

Alpha

Tips for using Alpha with Unreal Engine assets:

  • Alpha content should be set to Premultiplied Alpha in Disguise.

  • PostProcessingMaterials do not support alpha from Unreal Engine.

  • Set post processing and effects quality to high/cinematic/epic.

  • Atmospheric fog will need to be disabled in channels rendering front plate alpha.

  • When a monitor is connected to a render node, ensure that there is 100% scaling to the native resolution. A second monitor can be used as the review screen if the GUI must be scaled.

  • Ensure there are no sky domes or full frame effects in the frontplate channels.

  • r.SceneColorFormat must be set to 4.

  • Turning on/off alpha or modifying the transport configuration in any other manner for Unreal assets will cause a shader recompilation and may take a considerable amount of time before the content is visible within Designer.

  • Try hiding post processing methods one by one within the RenderStream Layer as a troubleshooting test if you are not getting alpha through.

Limitations

Limitations of using certain Unreal Engine effects with RenderStream.

There are a number of default options in Unreal Engine that are not suitable for use with any splitting strategy in a Cluster pool. In some cases this is because the whole image is required to be present in order to work; this can sometimes be mitigated with padding and overlap, but this must be evaluated on a case by case basis. In other cases it is because additional buffering is required.

The RenderStream Channel Definition component settings contain flags allowing many of these to be enabled / disabled on a per-channel basis.

Below is a non-exhaustive list of such effects:

  • Depth of Field
  • Bloom
  • Vignette
  • Lens Flare
  • Temporal Anti Aliasing (TAA)
  • Screen Space Global Illumination (SSG)
  • Screen Space Ambient Occlusion (SSAO)
  • Screen Space Reflections (SSR)
  • Raytracing (denoiser)
  • Chromatic Aberrations
  • Eye Adaption
  • Motion Blur

Post Process Volume

By default, Unreal Engine automatically sets the exposure of a map’s PostProcessVolume. This can cause the exposure of split frames to be different, revealing a noticeable seam between frames. To correct this here are some suggested settings:

  • xpand the Lens property of PostProcessionVolume.
  • Expand Exposure.
  • Change the Metering mode to Manual.
  • Adjust the Exposure Compensation.
  • Exposure Compensation can either be a user defined float value appropriate to the scene, or a Float Curve can be applied.
  • Be aware there are exposure settings within camera and cinecamera objects; ensure they are set to manual exposure as well.