Normal-map QA video · 35 seconds

Five normal-map mistakes that make materials look wrong

Spot inverted green channels, sRGB sampling, misaligned UVs, excessive strength, and invalid rotation before a normal map reaches production.

Reviewed by the PLAYTEX AI Editorial Team · Updated

PLAYTEX AI technical workflow · 35 seconds · English captions

Direct answer

What should you do?

The most common failures are the wrong Y convention, treating vector data as sRGB color, changing crop or orientation without transforming tangent vectors, using strength to hide a bad height source, and approving the map from one fixed light. Diagnose each with a neutral material and a moving white light.

Video chapters

  1. 0:00 — Establish the expected surface

    Know what the source should look like before diagnosing vectors.

  2. 0:05 — Match the source and convention

    Separate source mode from the renderer normal Y convention.

  3. 0:10 — Inspect the normal within the full stack

    Look for alignment, color-space, and channel-role errors.

  4. 0:16 — Tune strength under moving light

    Use response, not purple appearance, to judge direction and intensity.

  5. 0:22 — Preserve deterministic transforms

    Rotate or convert vectors with a normal-aware operation.

  6. 0:27 — Verify the engine import

    Confirm convention and data sampling in the actual renderer.

Step-by-step implementation

  1. Confirm tangent space. Verify the file is a tangent-space normal rather than object-space data or an ordinary purple image.
  2. Check the Y convention. Test OpenGL Y+ and DirectX Y- with a moving light; record the chosen source and output conventions.
  3. Check import and transforms. Disable sRGB, use the renderer normal role, and apply vector-aware rotation or channel conversion.
  4. Validate strength and seams. Inspect grazing light, tile boundaries, mirrored UVs, and compression at the target camera distance.

Key decisions

  • A green-channel flip converts Y convention; it does not repair every inverted-looking normal.
  • Tangent-space normal maps are vector data and should not be sampled as sRGB color.
  • Rotating the bitmap without rotating encoded X/Y vectors changes the represented surface direction.
  • The final truth is the material response under moving light in the target renderer.

Key frames and map details

Normal map channel review showing tangent-space RGB data and shaded material response
Judge the encoded vectors by the rendered response, not by whether the bitmap looks purple.
OpenGL Y plus tangent-space normal map used for convention checks
Record the normal convention next to the source file.
PBR texture set rotator with normal-map convention and vector-aware transform controls
A normal-aware rotation transforms X and Y vectors instead of only moving pixels.

Vector-aware 90° clockwise transform

Decode RGB to tangent vector X, Y, Z.
Normalize the input convention to canonical Y+.
For 90° clockwise: X' = Y; Y' = -X; Z' = Z.
Renormalize, encode the requested output convention, then preserve alpha.

How to know the result is correct

Use a neutral gray material, zero metallic, medium roughness, and one movable white light. Features should bulge and recede consistently from every light direction, seams should remain closed, and the same convention must survive the actual engine importer.

Video transcript

  1. 0:00 Begin with one source and a known material response.

  2. 0:05 Image, procedural, and hybrid source choices stay separate from normal-map convention.

  3. 0:10 Inspect the normal map alongside albedo, roughness, metallic, AO, height, and emission.

  4. 0:16 Tune normal strength while the physical response updates under light.

  5. 0:22 Repeatable settings keep conversion and rotation choices reviewable.

  6. 0:27 Export for the destination renderer and perform the final convention check there.