Normal Maps and Baking, Done Properly
Normal maps store the direction a surface faces at each pixel, letting a low-polygon model look detailed; baking is the process that transfers that detail from a high-polygon version.
Imogen Clarke
Why does it matter?
Baking is how real-time and web assets look detailed within a polygon budget, and a wrong setting produces seams, artifacts or lighting that looks inverted.
What are the numbers?
- Normal map per-pixel surface direction that fakes detail without extra geometry
- Tangent-space normal maps the usual type for assets that deform or are reused
- Green channel convention OpenGL style in Blender and Unity, DirectX style in Unreal Engine
- Baking projecting detail from a high-poly model onto a low-poly model's textures
- Cage or ray distance controls how far the bake searches between the two meshes
What should I do?
- Match the low-poly silhouette closely before baking
- Split UVs at hard edges to avoid shading seams
- Use a cage or tuned ray distance for complex shapes
- Confirm the green channel convention for the target engine
- Check the bake under moving lights, not just one angle
What should I avoid?
Avoid:
- Baking with overlapping UVs that are not meant to share texture
- Mixing normal map conventions between tools
- Expecting a normal map to fix a poor silhouette
- Compressing normal maps with settings meant for color textures
When should I get help?
Short answer Bring in help when baked assets show seams or inverted lighting, or when a high-detail model must run in a browser or game engine.
Where this comes from
- Blender Foundation — Blender manual: Render baking
- Unity Documentation — Normal map (bump mapping)
- Unreal Engine Documentation — Textures
The figures and practices above come from the sources listed.
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Where to go next
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