DCC production guide
Normal Map Green Channel Fix Guide
Direct answer: If dents look raised or raised details look sunken, first check the normal map Y convention. DirectX-style and OpenGL-style normal maps differ in green-channel orientation. Flip the green channel only where the pipeline requires it, and avoid compensating twice in both texture and shader.
DirectX NormalOpenGL NormalFlip Green ChannelMikkTSpaceFlipped Normal绿色通道翻转法線マップ
Y convention test
Place the asset under one neutral side light. Compare a known bump or engraved detail against the high-poly source. If vertical lighting appears inverted while red-channel horizontal lighting looks plausible, the green channel is likely wrong.
Tangent basis matters
Green-channel orientation is not the only normal-map issue. The baker, DCC viewport, and engine should use compatible tangent space, commonly MikkTSpace in many realtime pipelines. A tangent mismatch can create seams even when the Y direction is correct.
Import settings
Normal maps should be imported as normal data, not base color. Compression, sRGB flags, channel swizzles, and texture type settings can all alter the result. Recheck after platform texture compression because some artifacts appear only in final build settings.
Related geometry checks
Before rebaking, inspect face orientation, mirrored UV seams, hard edges, and overlapping faces. A flipped normal map can hide geometry problems; fixing Y orientation should not become a substitute for clean mesh normals.
Approval workflow
Document whether the target expects DirectX or OpenGL normals, show the before/after lighting comparison, and keep the bake preset. If the project uses a shader-side flip, state that clearly so texture artists do not flip the source map again.
Worked review example
For a riveted metal panel, choose one rivet that is visibly raised in the high-poly source. In the engine preview, rotate a single light from top to bottom. If the top half of the rivet shades as if it were a dent, the Y direction is suspect. Flip green once and repeat the test. If seams remain along UV borders after the rivet reads correctly, investigate tangent basis and split normals instead of flipping the map again.
Multilingual production terms
Use this normal map green channel fix guide terminology table when writing review comments, export notes, or handoff instructions across Chinese, English, and Japanese teams.
| 中文 | English | 日本語 | Workflow usage note |
|---|---|---|---|
| DirectX 法线 | DirectX Normal | DirectXノーマル | Use these terms when documenting normal-map convention, tangent basis, and Y-channel fixes. |
| 绿色通道翻转 | Flip Green Channel | 緑チャンネル反転 | Use these terms when documenting normal-map convention, tangent basis, and Y-channel fixes. |
| 反转法线 | Flipped Normal | 反転法線 | Use these terms when documenting normal-map convention, tangent basis, and Y-channel fixes. |
| MikkTSpace | MikkTSpace | MikkTSpace | Use these terms when documenting normal-map convention, tangent basis, and Y-channel fixes. |
| OpenGL 法线 | OpenGL Normal | OpenGLノーマル | Use these terms when documenting normal-map convention, tangent basis, and Y-channel fixes. |
Term notes for multilingual briefs
Use the English term Flip Green Channel with matching Chinese/Japanese notes where relevant: Flipped Normal / 绿色通道翻转 / 法線マップ. Keep the technical term beside the local-language note so reviewers can map it back to DCC and engine settings.
Related pages and next step
Open SEELE AI workspaceFAQ
What does flipping the green channel do?
It inverts the normal map Y direction, switching between common DirectX-style and OpenGL-style interpretations.
Should I flip every normal map for Unreal or Unity?
Do not use a universal rule without checking the project import settings and shader convention. Verify with a known lighting test.
What is MikkTSpace?
It is a tangent-space convention used by many realtime pipelines to make baked normals match engine shading more predictably.
Why do seams remain after flipping green?
The cause may be tangent mismatch, UV split mismatch, hard edges, mirrored UVs, or compression artifacts rather than Y orientation.