What is Shading? • Assigning of a color to a pixel in the final image. • So, everything in shading is about how to select and combine colors to get the look you want.
What impacts shading? • The lights in a scene. • The geometry of objects in a scene. • The normals of objects. • The shader properties of an object: • Color,transparency, emissivity, etc… • The rendering algorithm • Eg ray-tracing versus scan-line rendering.
The Original CG Shading Techniques • Faceted Shading • Smooth Shading • Specular Shading
What is a Normal? Eyepoint Light Normal Reflected Light Plane Eyepoint Normal Reflected Light Plane
Next: Surface Shaders • A grouping of all variables that influence the rendered color of a 3D object. • Surface finish • Simulated material. • Surface libraries/material databases. • Surface Layers • RenderMan Shading
Surface Layers • Combine multiple shaders for astonishing effects. • Build up shades like a painter.
Renderman Shaders • Renderman is a procedural shader language with tremendous versatility. • All major feature animated feature films use Renderman as part of production. • Like programming in C code. • You write Shaders for Renderman like you would write C code for computers.
Image Mapping • Generally referred to as Texture Mapping. • 2D Texture Mapping • Creating the map • Maps for real-time • Maps for feature film
Surface Reflectivity • Ambient Reflection • Diffuse Reflection • Specular Reflection • Reflection maps • Environment Maps • Glow/Incandescence
Surface Texture/Roughness • Visual textures – like brick wallpaper. • Spatial textures/roughness – mod geometry. • Bump maps – modify surface normals. • Displacement maps • 2D Procedural `Texture’ maps. • 3D Procedural `Texture’ maps.