Cycles

Cycles is Blender’s path-tracing render engine that simulates light in a physically realistic way. It computes global illumination, realistic shadows, reflections and refractions by tracing light paths, making it well suited for high‑quality final renders and productions where physical accuracy matters. Cycles can run on CPU and GPU (CUDA, OptiX, HIP, Metal depending on platform) and supports advanced features like subsurface scattering, caustics, volumetrics and denoising, but it is generally slower than real‑time engines like Eevee. Because it integrates tightly with Blender’s material node system, Cycles is a key tool in 3D modeling and shading pipelines for photoreal output.

You created a 3D interior model and want a photoreal product shot. You use Cycles so HDRI lighting and physically based materials (glass, metal, fabric with subsurface scattering) react correctly to light, increase the sample count to reduce noise, and enable denoising for a cleaner result. Because Cycles renders slower than Eevee, you first do quick test frames with lower samples and bounces, then switch to GPU rendering with OptiX or CUDA for the final pass and export multiple render passes (diffuse, glossy, AO) for compositing in post.