Take a look at these important notes that will influence the "Smart Weathering” node behavior
This solution is meant to be used with Cycles only.
To correctly preview the effects we recommend doing it with “render” mode and with cycles for the same reason as explained above.
Please, check that your object “Scale” is set to “1” in all the axes (x, y, and z). If not, the textures will probably look stretched. To reset the scale of the object you can use the “Ctrl+A” shortcut and then use the “Scale” option. Check this tutorial to better understand this.
Ensure using a “Texture Coordinate” node to map the textures. To properly create the effects it has to be used in the “Object” output option. You can also pick a reference object to have better control and consistency ****of the textures that will be applied and to avoid unwrapping the objects. The recommended option to pick is the standard “cube”, but what really matters is that the reference object has a proportional scale: x=1, y=1, and z=1. Check this tutorial to better understand this.
Changing (moving, scaling, or rotating) the reference object of the texture coordinate node, will change the final output of the SW (seed of the texture effect and its scale). It is not recommended to rotate it too much as it will distort the textures applied. Check this tutorial to better understand this.
The “Smart Weathering” node group can be used only once in the material configuration. Adding an SW node right after the previous one will give you a completely black material output. That is why the recommended way to use it is as the last layer of your setup and should directly connect to the “Surface” input of the “Material Output” node. Keep in mind that previously to connect to the SW you can still create complex materials (by mixing them).
To ensure that all effects work as properly, avoid using either low poly meshes with smooth shading (and no auto-smooth enabled). For instance, if you use low poly meshes smoothed the "Scratches on edges" effect will not recognize the edges that are sharp and will probably give you weird results.
We recommend not to change the name of the node and also not to change the variables that are in it because if you do the add-on will not work properly.
As the SW tool is a quite heavy effects layer it is recommended to simplify and optimize your base shader setup the most as possible. For instance, a “PBR Principled BSDF” + SW would be the most efficient way to achieve the desired material.