fix: use Y axis for LODGroup size to fix early LOD culling

[dalkia]

Summary

• Use mergedBounds.size.y instead of max axis for LODGroup.size, reducing inflated CullRelativeHeightPercentage on wide/long scenes that caused LODs to disappear too soon
• Improve non-square texture warning to include texture name and dimensions for easier debugging

Test plan

• Verify LOD_1 remains visible at expected distances for multi-parcel scenes
• Check that small single-parcel scenes still cull correctly
• Confirm non-square texture warnings now show texture name and resolution in logs

🤖 Generated with Claude Code

[github-actions]

Windows and Mac build successful in Unity Cloud! You can find a link to the downloadable artifact below.

Name	Link
Commit	054de54
Logs	https://github.com/decentraland/unity-explorer/actions/runs/24408789209
Download Windows	https://github.com/decentraland/unity-explorer/suites/64590045369/artifacts/6432623227
Download Windows S3	https://explorer-artifacts.decentraland.org/@dcl/unity-explorer/branch/fix/lod-visibility-improvements/pr-21063-054de54/Decentraland_windows64.zip
Download Mac	https://github.com/decentraland/unity-explorer/suites/64590045369/artifacts/6432624178
Download Mac S3	https://explorer-artifacts.decentraland.org/@dcl/unity-explorer/branch/fix/lod-visibility-improvements/pr-21063-054de54/Decentraland_macos.zip
Built on	2026-04-14T16:24:50Z

[claude]

Claude finished @dalkia's task in 1m 20s —— View job

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Summary

Both changes are correct and well-targeted. No issues requiring fixes were found.

SceneLODInfo.cs — LODGroup.size calculation (Explorer/Assets/DCL/LOD/Components/SceneLODInfo.cs:129)

The fix is sound. Unity's LODGroup uses screen-relative height (vertical axis projection) to evaluate LOD transitions, so using mergedBounds.size.y directly is semantically correct. The old Mathf.Max(x, y, z) approach inflated size for wide/long scenes (e.g., a 2×10-parcel scene with large X/Z footprint), causing CullRelativeHeightPercentage to be higher than warranted, and LODs to cull prematurely.

One edge case to be aware of: very flat scenes (small Y, large X/Z) will now produce a small size, yielding a low CullRelativeHeightPercentage. This means the LOD lingers visible until it's nearly imperceptible on screen. The existing Mathf.Clamp(..., 0.02f, 0.999f) in CalculateCullRelativeHeight guards against degenerate values, so this is a bounded and acceptable trade-off.

LODUtils.cs — Warning message (Explorer/Assets/DCL/LOD/Systems/LODUtils.cs:45)

Straightforward improvement. TEMP_MATERIALS[j].mainTexture is guaranteed non-null by the outer if guard, so no null reference risk in the added string interpolation.

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REVIEW_RESULT: PASS ✅
COMPLEXITY: SIMPLE
QA_REQUIRED: YES

[github-actions]

Auto-approved by Claude — simple fix/chore with no blocking issues. QA approval is still required.

[claude]

Claude finished @dalkia's task in 1m 28s —— View job

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• Gather context
• Read changed files
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Review Complete

No blocking issues found.

SceneLODInfo.cs:129 — LODGroup.size now uses Y axis

The fix is correct. Unity evaluates LOD transitions by comparing the object's screen-relative height, so mergedBounds.size.y is the semantically right value. The old Mathf.Max(x, y, z) inflated size for wide/long scenes (large X/Z footprint, e.g. multi-parcel plazas), causing CullRelativeHeightPercentage to be larger than warranted and LODs to cull prematurely.

The one edge case — very flat scenes (tiny Y, large X/Z) — produces a small size and a low CullRelativeHeightPercentage. This keeps the LOD visible until it's nearly invisible on screen, which is the correct trade-off. The Mathf.Clamp(..., 0.02f, 0.999f) in CalculateCullRelativeHeight handles near-zero Y gracefully.

LODUtils.cs:45 — Enriched non-square texture warning

Safe and correct. TEMP_MATERIALS[j].mainTexture is guaranteed non-null by the if guard at line 41, so accessing .name, .width, .height in the interpolated string is safe. The warning now provides the exact texture name and resolution to make debugging easier.

Asset bundles (25 files)

Test assets added for reproducing the fix. These are binary blobs in StreamingAssets/AssetBundles/lods/. Not an issue for the fix itself, though test-only binaries in the repo will permanently inflate clone size — worth cleaning up in a follow-up if they are not needed long term.

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REVIEW_RESULT: PASS ✅
COMPLEXITY: SIMPLE
QA_REQUIRED: YES

[github-actions]

Auto-approved by Claude — simple fix/chore with no blocking issues. QA approval is still required.