Well, thank you @luchian for the post. I learnt my basic knowledge on this post. Right now, I am working on a huge (about 5km by 5km) open world map using blender 2.79 , but when I was testing the visual effect on a certain section, I noticed the car somehow moves irregularly when it was stationary. Or I should say it feels like the road is wavy, and the car just float on it. After countless of tests, I found the issue occurs when the car is further away from the global origin and nothing wrong as long as I brought the car closer to the origin. I wonder if anyone has a similar problem? Or if I have done something terribly wrong.