Painting on the 2D canvas is useful when you need to create a texture to be applied to a surface. For example, suppose you paint a repeating brick pattern on the canvas and save the canvas as an image file. You can create a material, for instance, a Blinn material, then apply the image file as a file texture to the color of the Blinn material. You can then apply the Blinn material to a 3D wall you’ve modeled, which creates the illusion of a brick wall.
Painting a 2D canvas is also useful for creating a background image for a scene. For instance, you might create lush foliage on the canvas, put it on a camera’s image plane, then use it as the backdrop for animated jungle animals in the foreground.
Although not covered in this lesson, you can use a tablet and stylus to paint with pressure sensitivity. Pressure sensitivity allows you to more realistically simulate the effects of traditional drawing media (pens, pencils, markers, etc.)