Usage — Blender Shaders & Nodes¶

Opening the right editor¶

Blender's top bar has workspace tabs. The relevant ones:

• Shading — 3D Viewport + Shader Editor. Use for materials.
• Geometry Nodes — 3D Viewport + Geometry Node Editor. Use for procedural modeling.
• Compositing — Compositor view. Use for post-render effects.

You can also split any area manually: right-click the area border → Vertical Split / Horizontal Split, then change the editor type from the dropdown in the area's header.

Shader Editor anatomy¶

• Header dropdowns select the context: Object (materials on the active object), World (environment), Line Style (Freestyle).
• The output node (Material Output) is the root of evaluation. The Surface input is what you're building. Volume is for in-volume scattering (smoke, fog). Displacement is true displacement (Cycles only, with Experimental feature set).
• Nodes are added with Shift+A.
• G grabs, X deletes, Ctrl+G groups selected nodes into a reusable group, Tab enters/exits a group.
• Ctrl+Shift+click on any node routes its output to a temporary viewer via Material Output — incredibly useful for debugging graphs.

Sockets and data types¶

Socket color = type:

• Gray — float (scalar)
• Purple — vector (3 floats; position, normal, UV, etc.)
• Yellow — color (RGBA; auto-converts to/from vector and float with implicit math)
• Green — shader (a BSDF or mix of BSDFs — not a color, a function)
• Light blue — string (Geometry Nodes)
• Teal — geometry (Geometry Nodes)
• Red-orange — object, collection, image, material (reference sockets)

Implicit conversions happen automatically when you connect mismatched types. A color → float conversion takes the luminance; a float → color broadcasts to grayscale.

How a shader is evaluated¶

Cycles / EEVEE Next shade each visible point on a surface. For that point they:

1. Compute all input values (texture sampling, coordinates, math).
2. Plug into the BSDF mix you've built.
3. Ask the BSDF for a color given the incoming light direction and outgoing view direction.

Practical consequence: nodes are evaluated per shading point. Heavy procedural noise is run every pixel, every frame in EEVEE and every sample in Cycles. Optimize accordingly.

Geometry Nodes anatomy¶

• Add a Geometry Nodes modifier to an object, then create/edit a node group inside the Geometry Node Editor.
• The group inputs/outputs appear on the modifier in the N-panel — this is how you expose parameters to the artist driving the object.
• Geometry flows through the teal socket. You modify it by chaining nodes like Set Position, Instance on Points, Join Geometry.
• Fields are a Geometry Nodes specialty: a socket can carry a function that evaluates per element rather than a single value. Position is a field — it's a different value per vertex. Fields let one node (e.g. Set Position) apply per-element logic without an explicit loop.
• The Domain of a field matters: point, edge, face, corner, spline, instance. Use Capture Attribute to lock a field's value in a specific domain, and Evaluate on Domain / Interpolate Domain to change it.

Compositor anatomy¶

• Enable Use Nodes in the header if starting fresh.
• Input: Render Layers (your render) or Image. Output: Composite (final frame) and Viewer (preview).
• Operates on 2D image data — color, vector, and single-channel passes.
• Passes (depth, normal, mist, cryptomatte) are separate outputs of Render Layers that you route to fx nodes.

Useful keyboard shortcuts¶

Common gotchas¶

• "My shader is black." You probably forgot to plug into the Surface input of Material Output, or you're in Rendered view but no lights/HDRI exist.
• "Noise pattern looks wrong in viewport but right in render." EEVEE Next and Cycles differ for some nodes (especially ones involving raytracing, true displacement, or subsurface). Always spot-check in both.
• "Geometry Nodes field is flat/wrong." You're evaluating a field on the wrong domain. Capture Attribute on the correct domain (usually point) fixes this.
• "UVs look stretched." You're using generated coordinates instead of UVs, or the object hasn't been UV-unwrapped.