Introducing materials
As we mentioned in the introduction, materials are assigned to objects. However, you can’t assign materials to all objects. When you start up a new Blender file, it comes with a cube, a camera, and a light object. Only one of these objects has substance from Blender’s perspective, and that’s the cube. Let’s break this down a bit more to understand why it matters. Although a camera and a light source have physical properties and they occupy space in real life, this isn’t the case in Blender. They are conceptual objects.
A camera is a tool through which you see the world. So, you don’t get to see the visual properties of the camera itself. It doesn’t matter if the camera is painted red or blue. Similarly, a light source shines a bright or dim light, sometimes with a certain color, but it doesn’t take up space in a Blender scene. Therefore, if there is no substance, we can’t apply a material to these...