Transitioning From Blender Internal To Cycles Materials And Textures
Understanding Blender’s Render Engines
Blender Internal is Blender’s original scanline rendering engine that uses a fixed pipeline approach to determine shading and lighting. It relies primarily on preset shader settings rather than node networks. Cycles is Blender’s physically-based path tracing engine introduced in 2011. It utilizes node-based materials and more accurately simulates real-world physics and lighting.
Blender Internal vs Cycles: Core Differences
Cycles materials use shader nodes rather than fixed settings for greater flexibility. These nodal networks determine the surface appearance and properties by connecting colors, maps, values, and vector inputs to shader nodes like Diffuse, Glossy, Glass, etc. Blender Internal relies more on fixed categories like Diffuse, Specular, Mirror, etc. with limited inputs.
Cycles computes lighting and shadows path-traced from lamps and mesh emitters. This advanced technique simulates realistic light physics. Blender Internal uses scanline rendering which applies preset lighting formulas per lamp object. Environment lighting is approximated or faked through ambient values and halo materials.
Why Switch to Cycles?
Cycles produces more photorealistic results due to its physically-based, ray-traced approach. Materials appear more lifelike and lighting behaves naturally resulting in soft shadows, indirect illumination, caustics, subsurface scattering and other optical effects. As GPU and CPU performance improves, Cycles will only become more versatile and production-ready.
Blender is phasing out Blender Internal development to focus on Cycles, Eevee, and new render technologies. Cycles receives frequent improvements with newer Blender releases. Transitioning from Blender Internal helps future-proof scenes and skillsets within Blender.
Porting Materials
Converting Default Settings
When porting Blender Internal materials, reasonable Cycles approximations can be created from the Diffuse, Specular, Mirror, and Emission settings. For example, a red diffuse color would translate to a Diffuse BSDF with connected Image Texture or RGB inputs. An intricate Material conversion is not always needed for reasonable Cycles results.
Reworking Texture Nodes
While Blender Internal relies heavily on fixed channels for color inputs, Cycles nodes offer greater texture manipulation with layers of math and vector operations to control properties like Roughness, Bump, Displacement, and more for improved realism. This power comes at the cost of intricacy. Strategic texture baking from Blender Internal can simplify this process.
Example Node Setups
A metal material with scratches uses a Layer Weight node to mix between a smooth and rough scratched texture. A worn paint material combines a ColorRamp controlling a Voronoi texture with a base color. An aged wood texturing uses noise textures to generate indentations and valleys associated with weathering over time through bump and displacement.
Updating Textures
File Formats
Blender Internal only uses JPEG images for texture inputs which get interpolated for display. Cycles can use higher-quality PNG images natively for reduced noise and richer details. 16-bit PNGs preserve gradients better. JPEG compression can create undesirable color banding which gets pronounced under path tracing.
Texture Spaces
UV unwrapping models allows precision texturing control versus procedural coordinates but requires added effort. Cycles’ Generated and Object texture spaces output reliable textures quickly. Certain texture effects like weathering or edge wear often overlay better in generated space.
Baking from Blender Internal
Baking adds texture directly to models for cleaner material networks. This collapses involved node structures into fewer Image Textures. Baking in Cycles can introduce noise so baking in Blender Internal may provide smoother results in some cases. Just ensure to bake in matching resolution and scale.
Optimizing Cycles Materials
Simplifying Node Networks
Lengthy Cycles networks create convoluted render layer nodes which impact performance. Compacting sub-networks into group nodes or baking complex textures as images simplifies traces. Node Wrangler’s Autoroute helps instantly clean up messy networks once complete.
Using Procedurals Over Images
Image textures require loading and decoding external files versus internally-generated procedurals. Nodes like Voronoi, Noise, Wave, Musgrave in controlled amounts add realism without inflation. Ensure ColorRamps follow textures to control intense outputs.
Setting Appropriate Sample Counts
Higher sample counts produce reduced noise but increase renders times exponentially. Start low with preview sampling rather than final quality. Add just enough to reduce fuzziness for the shot framing. Render farms tweak samples per pass to optimize throughput.
Extra Features
Principled Shader
The Principled shader combines multiple texture properties like diffuse, glossy reflection, subsurface scattering into one node. This unified input minimizes node clutter. Non-metal parametrization better handles dielectrics. Metals may still require layered shader mixing for accuracy.
Volumetrics
Volume shader nodes add atmospheric fog, smoke, fire, and other gaseous effects through ray marched absorption and scattering. Performance is highly sampling dependent. Only enable volumetrics on visible environmental elements rather than entire scenes.
Particle Systems
Emission shaders let particle systems naturally interact with scene lighting. This enhances explosions, fire, smoke, sparks. Use small draw counts and object pooling to optimize. Render visibility toggles help scale down particle noise and tracer load.
