A good way to understand 3D and animation is to look at a scene using the following five aspects. Understand how these work in any animation and the construction picture becomes clear.
Shape - What is the outline when viewed from all angles, how does the shape change over time ?
Size - What is the object size in relation to the environment and other shapes in the scene ?
Surface - What is on the surface and how does it handle the light ? Does the surface bend curve, grow stretch ?
Steps - Animation is movement. How does the movement break into steps ?
Space - What's in the the space around the object and how does it interact with its space ? What happens when the space around the object changes ?
Look at an animation or 3d scene using the definitions above. Study each aspect and separately and together and soon you will have insight.
Try it ...