In real-time rendering, reflections are simplified with approximations to meet performance needs, while offline rendering enables accurate, detailed reflection calculations without strict time constraints.
Real-time methods often use screen space reflections (SSR) or cube maps to simulate reflections quickly, prioritizing frame rate over perfect accuracy. Offline rendering, however, typically employs ray tracing or global illumination, tracing light paths to compute physically accurate, realistic reflections.
For video games or interactive apps, real-time reflections ensure smooth user interaction; for high-end visualizations or film, offline rendering with detailed reflections enhances visual fidelity.