Cycles Path Tracing Renderer

The default license for the Cycles source code is Apache 2.0.

Note that the repository also contains code adapted from other sources under different, but compatible, licenses. These specific files are identified using SPDX license identifiers and copyright notices within the source files themselves. To see a complete list of all licenses used within the codebase, refer to SPDX-license-identifiers.txt.

Cycles is cross-platform and supports GPU acceleration on the following hardware:

• Operating Systems: Windows, Linux, and macOS.
• GPU Architectures: NVIDIA, AMD, Intel, and Apple Silicon.

Cycles supports several texture categories for shading:

• Image Textures
• Environment Textures
• Procedural Textures
• Bump and Normal Maps

Cycles supports various geometry types and acceleration structures:

• Supported Geometry: Meshes, Curves, Points, Volumes, and Instancing.
• Motion Blur: Supported for moving geometry.
• BVH (Bounding Volume Hierarchy): Features multi-core BVH building and fast BVH refit updates for efficient ray-geometry intersection testing.

Cycles supports advanced surface detail through:

• Adaptive Subdivision: Dynamically adjusts mesh density.
• Subdivision Schemes: Supports Catmull-Clark and linear schemes.
• Displacement: Real geometry displacement based on textures or maps.
• Bump Mapping: Simulates surface detail without changing geometry.

Cycles uses a physically based shading model with a node-based workflow. Key features include:

• Principled BSDF: A unified shader for most material types.
• Open Shading Language (OSL): Support for extensible shading logic.
• Node-based workflow: For both shaders and lights.

Cycles supports a wide range of camera projections and optical effects:

• Projections: Perspective, Orthographic, Panoramic, and Fisheye.
• Stereoscopic Rendering: For 3D/VR workflows.
• Depth of Field: Simulates realistic lens focus.

Cycles handles volumetric effects including:

• Physical Properties: Absorption, scattering, and emission.
• Subsurface Scattering (SSS): For translucent materials.
• Volume Types: Supports both homogeneous and heterogeneous volumes.
• Principled Volume: A unified shader for volumetric materials.

Cycles provides several mechanisms for decomposing a rendered scene into constituent parts for compositing and post-processing:

• Render Layers: Used to separate different scene elements.
• Render Passes: Provides specific data for geometry and lighting components.
• Shadow Catcher: Allows integrating CG shadows into real-world photography.
• Holdout Mattes: Used for masking specific objects.
• Cryptomatte: Provides high-precision color-based ID masking.
• Denoising: Integrated tools to clean up stochastic noise.

Cycles is optimized for interactive workflows, supporting fast updates for objects, shaders, and lights. It employs two primary rendering strategies:

• Tiled rendering: Useful for high-resolution output.
• Progressive rendering: Allows for continuous refinement of the image, ideal for real-time feedback during scene adjustments.