Lighting is the soul of any 3D scene. Without proper light distribution, a design loses its realism. Modern techniques like Global Illumination simulate how light bounces off surfaces. Using IES profiles adds a touch of authenticity by mimicking real-world lamp patterns. Balancing soft and hard shadows creates visual depth. Ambient light must harmonize with wall colors for natural reflections. Mastering light temperature is key to setting the right mood for any interior space.