Unreal Engine Issues

UE-403591

Nanite Voxel material with Static Lighting fails shader compile when r.VelocityOutputPass=1

Nanite Voxel material with Static Lighting fails shader compile when r.VelocityOutputPass=1

Description

Engine/Shaders/Private/Nanite/NaniteVertexFactory.ush:959

LightMapCoordinateInput = GetTexCoord(Cluster, uint3(Verts[0].VertIndex, Verts[1].VertIndex, Verts[2].VertIndex), Barycentrics, LightMapUVIndex);

The Voxel path instantiates this function with N = 1, but the code always reads Verts[1] and Verts[2], which is out of bounds.

Steps to Reproduce
  1. Create a new project on UE 5.8
  2. Set the following settings in DefaultEngine.ini 
    [/Script/Engine.RendererSettings]
r.AllowStaticLighting=True
r.VelocityOutputPass=1
r.Nanite.Foliage=True
  3. Restart the editor
  4. Create a new material
  5. In the Details panel, Usage, enable “Used with Static Lighting”, “Used with Nanite” and “Used with Voxels”
  6. Press Apply button

Result:

Shader compile error occurs with the following:

21 Shader compiler errors compiling NewMaterial for platform PCD3D_SM6:

Internal Error!
	NewMaterial_bb2df57701f578a3/High/FNaniteVertexFactory/TBasePassCSTLightMapPolicyHQVoxel/1:/Engine/Private/BasePassPixelShader.usf|MainCS VF 'FNaniteVertexFactory' Type 'TBasePassCSTLightMapPolicyHQVoxel' '/Engine/Private/BasePassPixelShader.usf' Entry 'MainCS' Permutation 1 

Shader debug info dumped to: "D:\dev\ue508projects\VoxelRepro\Saved\ShaderDebugInfo\PCD3D_SM6\NewMaterial_bb2df57701f578a3\High\FNaniteVertexFactory\TBasePassCSTLightMapPolicyHQVoxel\0_ec2c0ef24d84ef31"

D:\dev\UnrealEngine-5.8.3\Engine\Binaries\Win64\BasePassPixelShader.dxil(6089,37): Shader TBasePassCSTLightMapPolicyHQVoxel, Permutation 0, VF FNaniteVertexFactory:
	BasePassPixelShader.dxil:6089:37: error: Instructions must be of an allowed type.
note: at '%1146 = insertelement <3 x float> undef, float %1137, i32 0' in block '#32' of function 'MainCS'.

...

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Unresolved
ComponentUE - Rendering - Features - Nanite
Affects Versions5.8
Target Fix5.9
CreatedOct 16, 2026
UpdatedOct 19, 2026
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