How to merge two normal maps in Blender
This method combines both the wrinkled bump effect and the material texture bump details, aiming to maximize the efficiency of texture resource usage. The seamless texture that can be repeated in all directions (for texture details) does not need to be very large in pixels; a single pattern is sufficient, while the wrinkled bump should be a large-sized bump. After connecting to the material node, it can ensure the clearest state. The specific node connection method is shown in the figure below.
The corresponding nodes are explained from left to right as follows:
Control Texture Repeat Node#
These two nodes, when using the shortcut key ctrl+t, will automatically connect to the downstream nodes.
Normal A#
Typically the object's wrinkled normal, with large texture pixels, so it does not need to be repeated, just this one.
Normal B#
Typically the object's texture details, such as the texture of a sweater or leather, which can be repeated seamlessly in all directions and scaled.
Therefore, the normal provided here must be able to be copied seamlessly in all directions (seamless texture).
Texture Blend#
The node that blends the two normals together, with the blending mode set to: Soft Light, as shown in the red box position in the image.
Normal Map#
Finally, connect the upstream blended node to this one, and output it to the normal node of the Principled BSDF material node.