Real-time rendering handles shadows with simplified, speed-focused methods, while offline rendering uses complex techniques for superior shadow quality.
Real-time often relies on shadow maps: these approximate shadows by projecting depth information onto a 2D texture, prioritizing quick computation over fine detail. Offline rendering, however, employs ray tracing to calculate light paths accurately, resulting in softer edges, penumbra effects, and realistic interactions with complex scenes.
In practice, real-time shadow methods suit interactive contexts like games, while offline techniques are ideal for high-quality static renders such as movies.