High Screen Percentage + Virtual Shadow Cache = Large shadow artifacts

Development Rendering
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Seen on the Steam build of Conan Exiles: Enhanced.

At a specific location on the map and certain Time of Day, the player is in a shadow cast by a large landscape-form, not dressed with static meshes.

Playing Full-screen windows, at 2560*1440, Ultra settings everywhere, framegen active, TSR at Native AA.

(The artifact is also visible with DLSS/DLAA)

With a Screen percentage above ~90%, and the VSM cache enabled, the solid shadows that should be cast from the landscape are patchy - changing with the stepped motion of the sun through the sky.

See Conan_Exiles_Enhanced _VSM_ScreenPercentage.mp4 - The Artifact under these rendering circumstances are severe; VSM pages are unstable and change dramatically with stepped Sun-motion (slowed down from regular runtime speed for visibility). Video also shows console command changes for CSM cache

See Conan_Exiles_Enhanced_Layout for the logistics in-world

See Conan_Exiles_Enhanced_VideoSettings for repro info

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Hi.

Questions:

  1. Is the artifacts specific to landscape?
  2. Is the landscape Nanite?
  3. Does anything change if you alter r.Shadow.Virtual.MaxPhysicalPages
  4. Does VSM stats show anything changing between the two modes?
  5. There may also be overflows in the Nanite queues, I forget whether we had feedback for those in 5.6.
    1. nanitestats virtualshadowmaps or in Test builds:
    2. r.Nanite.StatsFilter = virtualshadowmaps & r.Nanite.ShowStats 1

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Hi there Ola - I’ll provide answers I know right now, and research others.

1 - It seems so, yes; shadows cast from static meshes on the sunny side of the landscape are projected through and are visible in the artifact on the shadowed side.

2 - Yes. It is Nanite-enabled, and on Ultra quality, has tessellated displacement enabled (I dn’t remember if lower quality levels also have this issue; I will research this).

3 - No’ the requested pages in this area of the map seldom go above half the max physical pages allows - here it is 679 Requested / 1792 Max (Image attached)

4 - Between two modes - DLSS Vs TSR? (If so, I can research this)

5 - untested; I can research this, also.

Thanks - I’ll report back with missing data.

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With modes I meant between cached / uncached. But, with it being Nanite & tessellation enabled I’d focus on the Nanite buffer overflow investigation first, in Main the controlling cvars are

r.Nanite.MaxVisiblePatches

r.Nanite.MaxVisibleClusters

r.Nanite.MaxCandidateClusters

r.Nanite.MaxNodes

Not 100% sure if they have changed, but if not, you might try bumping those / the equivalent in 5.6 - should work while running.

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