What are the limits of normal maps? As far I understand, they can improve the appearance of a model, but how much can the appearance of a low-poly mesh be improved with the addition of a normal map? Can sharp edges appear as beveled because of a normal map?

I know normal maps don't change geometry, so I don't think you can make a pretty beveled cube out of the default cube just with a normal map. Is that right?


2 Answers 2


Normal maps simply trick the render engine into thinking that the face is at a differnt angle at that place. It cannot control height (It can still appear to create hight difference, but the are not accurate*) only angle.


- Changing the silhouette: normal maps won't change the outline

Another angle

- Accurate depiction of height

Working With Limitations:

  • Design your mesh to work with these limitations
    • make sure the silhouettes match
    • make sure all height differences are clearly define.
  • Adding enough supporting geometry to complete the illusion

The limitation of normal map is manipulation with the direction of surface normals. So you can influence how light will behave when interacting with the mesh.

Now this effect is dependent on the direction of light and position of camera against the surface, so if you try to do too much with normal map you will get distortions. Left Cube is original, right is Default cube with normal map. See how the corner facing camera is OK, but other corners are distorted due to not enough supporting geometry.

enter image description here


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