How to games render real time assets?

Thats usually because nothing changes in the games as far as shapes and movement when compared to 3D Modeling programs. Most if not all games have a loading screen which is where everything is pre-loaded in games. So when you see loading screens that is the time when textures, positions and statuses are loaded. Another ting is textures and lighting in games are not dynamic, they are static. The position of the player is dynamic but the objects and world is not. Everything is preset, from the textures to the movements of animated objects, to day/night cycles in certain games.. This being preloaded before the player enters the world make updating these things faster when the player interacts with them. So basically you can stand in a world that is alive and not know that each part was pre-lit. pre-animated and pre-textured. In 3D Modeling programs, when rendering, the renderer has to recalculate everything, even if you've made no changes (unless you bake all of these things into the models). Take Krakatoa for instance... As a particle renderer it can calculate millions on millions of particles super fast. It also has an option to save the position of millions of particles so you can remove the saved particles, add 100 million more, then load the other 500 million particles you have saved from a file in seconds (Krakatoa PRT). That method of technology, is what games use to render in realtime very quickly.