Directional Lightmap "stair stepping"

Questions & Answers
1

16147-expected.jpg

16148-stairstepped.jpg

The first picture is a model with a directional lightmap and the specular shader applied.
In the second picture, I have changed the shader to bumped specular, and added a flat blue normal map color = (128, 128, 255). I believe that they should look exactly the same. What is causing this “stair step effect”?

2

Answer: Mipmapping in the lightmap scale texture.

To fix this, change the lightmap scale texture type from “Lightmap” to “Advanced” and remove the mipmapping