3D objects can be rendered simplistic, such as a cube with flat-shaded faces, or very realistically, such as the same cube as a realistic wooden crate. This magic is performed with PBR materials and advanced Shaders.
A 3D object in Unity consists of a geometry mesh that defines the points, edges, and faces of the object, forming a surface that can then be rendered to appear as a solid object. Each object has a Renderer component that specifies the properties and behavior of this particular object rendered in the scene. It includes references to any Materials that will be applied to the object. A Material is an asset that specifies a specific Shader script that drives the actual work of drawing the object on the screen. You can learn more about all of this in the Unity Manual and Unity Learn sites, among many other resources. The following web pages provide more information:
- Best Practices Guide: Making...