Introduction
Cycles is Blender’s physically-based path tracer for production rendering. It is designed to provide physically based results out-of-the-box, with artistic control and flexible shading nodes for production needs.
To use Cycles, select it as the Render Engine in the Render properties. For GPU accelerated rendering, enable compatible devices in Preferences ‣ System ‣ Cycles Render Devices.
See also
The Cycles website with more information and a gallery.