I test it for more information for your reference:

  • It happens only when a Landscape *Height *was output to the RVT, other Landscape's maps like BaseColor are all fine, as well as Height output from other geometry like Staticmesh are all fine
  • It happens when the RVT volume was put in a Streaming level
  • It happens when using World Composition way to stream the level, it doesn't happen when using a regular Blueprint way
  • It only happens when the RVT is visible at first place when it's get streamed. Meaning if it's streamed behind the camera it has no problem. you can rotate the Playstart actor 180 degree play again to verify it.
  • Flush RVT cache using r.VT.Flush can fix the issue in runtime
  • If the RVT Volume was Put in the Persistent Level, the issue wouldn't happen
Steps to Reproduce
  • Open the Persistent Level in the attached Project(RVT_Issue) and Play
  • After running, the World Composition logic streamed in the sub level which includes RVT Volume, the Landscape outputting Height to RVT and a Plane mesh sampling the RVT.
  • The RVT caches Landscape's World Height then got sampled and fed into the Plane's material Emissive Color for Debug purpose
  • You can see pixelized RVT output from a landscape World Height; It looks like very low res RVT mip was loaded and can't be updated correctly while camera is moving

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ComponentUE - Rendering
Affects Versions4.27
Target Fix5.2
CreatedOct 13, 2021
UpdatedJul 20, 2022