Combine 2 normal maps (1 for layout and 1 for detail) So my question got closed when it is not even resolved.
here: How to use normal inside normal
So I want to combine 2 different normal map with different size.

Normal map for the object layout


this object normal map is in low poly.
Then I want to define the texture normal (like bump, etc) in another normal map:

The second image is the normal map for each small chunk piece of the texture. For example for every 1cm - 5cm of the texture should follow this normal map. So the 2nd image / the detail normal map should be repeated many times covering the whole texture.
How can I do this?
You can mix the 2 textures into a MixRGB node. Put the MixRGB factor at 0.5, and put the Normal Map strength at 2. As they are not supposed to have the same scale, they both use the same UV map but the first one will use a Mapping scale of 1 while you'll use a bigger scale for the second one (here x 10):