The way game designers and artists try to project the mode and presentation of objects in the game meets the frame by frame animation, or wisely use the physical aspects of Unreal Engine.
Twenty years ago, game designers animated the open and close movement of a simple door with the frame by frame method as an image-sequence file (such as GIF). Now, we can do the same in real time with light effects, materials, physical rules, and the blueprint code. Unreal Engine 4 provides the detailed properties and customizations for movements and dependency between objects in the game world. This is how creativity meets artistic details in a game design. Working with constraints is a kind of creative art.