To texture a 3D model with atlases without complex shaders, use a UV-unwrapped model and map your atlas texture to its UV coordinates via basic materials (like diffuse or Principled BSDF) in software such as Blender, Unity, or Maya.
Atlases combine multiple textures into one, so you only need a simple material that links the atlas to the model’s UVs—no layered or procedural shaders required.
For beginners, try Blender’s default Principled BSDF: connect your atlas to the Base Color input, then tweak the UV map if parts of the atlas don’t align. It’s a straightforward setup that skips complex shaders.