Games treat weapon only as a prop therefore, there is no need to imitate the mechanism working inside the model. It saves the amount of tris and assets. What is more it shortens the time required to prepare a model. There are usually the following exceptions:
- the inside of the optical devices,
- a magazine,
- a lock,
- the inside of the break-open kinds of weapons,
- the inside of pistols – slides, barrel, parts exposed while shooting,
- elements visible while reloading, e.g. the inside of a grenade launcher.
Showing mechanical elements aims only at creating a feeling of playing with a „real” thing. A player needs to believe in the illusion created by a graphic. Therefore, each movable element visible by a camera should be somehow justified, have shape and composition. The relation between them should not rise any concern of an onlooker.
Not many players have in-depth knowledge about weapon or machines’ construction. But seeing different kinds of mechanisms every day, people have adjusted some patterns and schemes, and subconsciously compare them with pictures they see, e.g. in games. If what they see does not match the imagination / pattern, they will question the authenticity of the world of game. Badly designed mechanism will not mislead the viewer.
Film by Feng Zhu is worth watching. He explains what, according to him, the contemporary design is and where to take the inspiration from.