stride3d/stride · error · ArgumentOutOfRangeException

Tried to access attribute index

Error message

Tried to access attribute index 

What it means

LightVoxelRenderer's GetTraceAttr throws ArgumentOutOfRangeException when the light's AttributeIndex is >= the number of entries in processedVolume.OutputAttributes. The index is zero-based and must select one of the voxel volume's output attributes for the light's trace. Typically this means the volume produces fewer attributes than the light expects.

Solutions

1. Set AttributeIndex to a valid zero-based index within the volume's output attribute count.
2. Re-select the correct attribute in the light component after changing the voxel volume's configuration.
3. Before querying, check AttributeIndex < processedVolume.OutputAttributes.Count and clamp or fall back.

Example fix

// before
var light = new LightVoxel { Volume = volume, AttributeIndex = 3 }; // volume has 2 attributes
// after
var count = volume.OutputAttributes.Count; // ensure <= count-1
var light = new LightVoxel { Volume = volume, AttributeIndex = Math.Min(3, count - 1) };

if (lightVoxel.AttributeIndex >= processedVolume.OutputAttributes.Count)
{
    lightVoxel.AttributeIndex = 0; // clamp to a valid zero-based index
}

bool HasValidAttributeIndex(LightVoxel lv, ProcessedVoxelVolume vol) =>
    lv.AttributeIndex >= 0 && lv.AttributeIndex < vol.OutputAttributes.Count;

try { attr = GetTraceAttr(); }
catch (ArgumentOutOfRangeException) { attr = processedVolume.OutputAttributes.FirstOrDefault(); }

When it happens

Trigger: Setting LightVoxel.AttributeIndex to a value equal to or larger than the voxel volume's OutputAttributes.Count, often after changing the volume's attribute configuration.

Common situations: Changing a voxel volume's baked attributes so a previously chosen index no longer exists; copying a light from another scene with a different volume; setting index 1 on a volume that only outputs one attribute.

Related errors

• No Voxel Volume Component selected for voxel light.
• Custom strides is not supported with packed PixelFormats
• PerView VoxelizerStorer layout differs between different…
• Graphics Profile Level 11 or higher required for…
• Render Stages required for voxelization, only

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/379e642f55f32f22. Report an issue: GitHub.

Appendix: source

Thrown at sources/engine/Stride.Voxels/Voxels/Light/LightVoxelRenderer.cs:130

                ProcessedVoxelVolume processedVolume = voxelVolumeProcessor.GetProcessedVolumeForComponent(lightVoxel.Volume);
                return processedVolume;
            }

            VoxelAttribute GetTraceAttr()
            {
                var lightVoxel = ((LightVoxel)Light.Type);

                ProcessedVoxelVolume processedVolume = GetProcessedVolume();
                if (processedVolume == null)
                    return null;

                if (processedVolume.OutputAttributes.Count > lightVoxel.AttributeIndex)
                {
                    return processedVolume.OutputAttributes[lightVoxel.AttributeIndex];
                }
                else
                {
                    throw new ArgumentOutOfRangeException("Tried to access attribute index " + lightVoxel.AttributeIndex.ToString() + " (zero-indexed) when the Voxel Volume Component has only " + processedVolume.OutputAttributes.Count.ToString() + " attributes.");
                }
            }
            public override void UpdateLayout(string compositionName)
            {
                base.UpdateLayout(compositionName);

                traceAttribute = GetTraceAttr();

                intensityKey = LightVoxelShaderKeys.Intensity.ComposeWith(compositionName);
                specularIntensityKey = LightVoxelShaderKeys.SpecularIntensity.ComposeWith(compositionName);

                diffuseMarcherKey = LightVoxelShaderKeys.diffuseMarcher.ComposeWith(compositionName);
                specularMarcherKey = LightVoxelShaderKeys.specularMarcher.ComposeWith(compositionName);
                attributeSamplersKey = MarchAttributesKeys.AttributeSamplers.ComposeWith(compositionName);

                if (traceAttribute != null)
                {
                    if (((LightVoxel)Light.Type).DiffuseMarcher != null)

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