Creating doubts is just the first step

Read the Big two o'clock, feel that build the game world interesting, but did not understand. Now in the game company for two years, has been fulfilled, but still feel the understanding is not thorough.

The first question to ask is: How to simulate a real world through a computer.
In fact, the above problems can be modified, that is: people to get through the computer to obtain what kind of visual experience, will think the computer world and the real world is very similar .
The question is, in fact, a good answer: the rules of motion of objects in computers must conform to common sense.

1. We first break apart the words used in that sentence, the noun is the focus of human thinking.
The nouns are: a. Computer B. Object C. Law of Motion D. Common sense
A. The term computer is useless.
B. What objects are called objects. Objects are what people see, things that are useful to humans in common sense.
C. The law of movement
D. Common Sense Newton's various nth laws
2. We collate the analysis of just nouns
How to make the motion of the object in the computer must conform to common sense.
That's what we see on the computer. The laws of motion conform to Newton's various nth laws .
This answer is expressed by computer, in fact, two words.
1. Let the display draw objects
2. Make the motion of the object in the display conform to common sense (Newton's various nth laws)

I have seen the game engine unity and our game engine is the same way to solve the above two words.
1. Let the display draw the object--rendering system
2. Make the motion of the object in the display conform to common sense (Newton's various nth laws), physical system
3. The idea of the component (component) tree is to associate objects in the physical system with objects in the rendering system, and then synchronize their location.

I don't want to talk about how the rendering system is structured, and I don't want to discuss what the physical system is like, although I'm particularly interested in the latter. What I want to talk about is why I want to solve this problem by binding the objects in both systems, rather than having the rendering system and the physical system together, and then having the created object directly owning all the properties of both.
or let the object that is created have a physical engine and a rendering engine. Then the rules of rendering and the rules of physics are obtained from the engine.