How to bake textures

With texture baking, you can combine multiple textures into one.

• Select all meshes and Ctrl+J (join)
• Create New texture
• Copy to all materials and click the node again make sure they are selected (WHITE OUTLINE)
• Make new UVMap and select it
• Enter Edit mode and UV -> Unwrap Minimum Stretch
• Render Engine -> Cycles
• Bake Type: Diffuse Bake, Contributions: Color
• Hit bake

Now you should have something like this, so save that to somewhere and make new material from it.

credit: Saber by 流云景