https://sims4studio.com/thread/861/normal-maps-bump-editing-creating

A brief explanation - a normal map is, well, a bump map, why it is called normal is beyond me, so from here on in I am going to refer to at as a bump map . The bump map is texture that is used on items within the game (any game) that gives the illusion that something has more detail than it actually has. Bumps combined with shadow maps is the reason why painted on clothing does not not look painted on. If you alter the texture, mesh or both on an object or CAS item that has an existing bump map you have to edit it as well, you can do one of three things, delete it, edit it, or make a new one, Ill explain each.

I'm not going to go through the whole process of showing you how to make one (well turns out I sort of have lol), they are relatively simple, likewise I am assuming if you are reading this you understand the basics of editing the DDS and the role of the alpha channel.

The bump (or normal) is in the warehouse section of S4S. You must select create 3D mesh for S4S to be able to pull the bump map out, it wont with the recolor option.

And it is here at the top

For object items it is here somewhere (I do no know if it stays in same position)

So if you do some editing on the shape of the texture, ie deleted part of it to reshape it, the bump map underneath will show through, the most simple thing to do is, is to replace the whole thing with a blank one.

To do so, simply export it in your 2d editor (photoshop gimp paint.net etc) select the same color as the grey and paint over it, remembering to do the same with the alpha layer, then import it back in and save.

That will fix your immediate problem, but you will also lose all that lovely detail that bump provides, so method two is to just edit out the bits you don't want.

With CAS items its a bit of a pain because the size of the image and the size of the bump differs so its a bit of guess work, but basically where you deleted texture, delete bump as well. (Remember to do the alpha layer too)

For objects its the exact same process, but its a bit easier as the bump and the texture, if not the same size, are the same dimensions, so you can layer one on top the other and line them up. (You can layer CAS ones too but its trial and error sometimes to get it sit right.)

The third option is make a brand spanking new one yourself. Ill explain in my next post, so grab a coffee, get rid of any children, take the phone off the hook, lock the door and prepared for 3 hours of hell. Nah, I is joking, its one the simplest things to do