help-render of "only" the sight of the camera

I HAVE A BIG QUESTION!

Is there a way to make the render “only” of a piece of the scene?

I mean…when I make the rendering of an Animation, blender for each frame calculate the render for all the objects also for the objects out of sight for the Camera and it’s toooo slow…

How could obtain something an animation which looks like Videogames like Unreal or something that use a real time engine …
For these videogames the camera and the animation are in real time…

Why don’t you go to potato mode (CTRL+Z) go to camera view (NUMPAD 0) and press ALT+A to make your animation run?

It is the fastest you can get in Blender…

Stefano