The Animation ProcessThe Animation Process

Lighting:Lighting:Illusions of IlluminationIllusions of Illumination

Lighting = realism

Although real people versus real clay/plastic Although real people versus real clay/plastic is up to texturesis up to textures

Realistic lighting = render timeRealistic lighting = render time

Some properties of lights

ColourColourBrightnessBrightnessShadow-castingShadow-castingVolumetricVolumetric

Types of lights : directional light

Also known as sun Also known as sun (light), infinite light(light), infinite lightParallel raysParallel raysSame lighting at any Same lighting at any point in the scenepoint in the scene

Types of lights : point light

Also known as bulb Also known as bulb light, omni light, local light, omni light, local light light Spherical volumeSpherical volumeFall-off is possible Fall-off is possible (distance)(distance)

Types of lights : spotlight

Also known as kliegAlso known as kliegRadius – limited areaRadius – limited areaFall-off is possible Fall-off is possible PenumbraPenumbraSoft shadows are Soft shadows are possible (can be possible (can be simulated with a simulated with a cluster of point lights)cluster of point lights)

A word about ambient light

Can be set for each Can be set for each object, or sometimes object, or sometimes can be set for entire can be set for entire scenesceneSimple 3D may use Simple 3D may use only ambient lightingonly ambient lightingCan be simulated Can be simulated with light at camera with light at camera positionposition

100% ambient lighting

Texture without lightingTexture without lightingUsually renders very Usually renders very fastfastUsed for games & VRUsed for games & VRDrawback : lack of Drawback : lack of shadows can look weirdshadows can look weirdWorkaround: use a Workaround: use a light-mapper, which light-mapper, which “bakes” lighting and “bakes” lighting and shadows into the shadows into the texture maptexture map

Traditional 3-point light setup

Main lightMain lightFill light (one or more)Fill light (one or more)Rim lightRim lightMay need to be set up for each camera angleMay need to be set up for each camera angle

Light example: “model” lighting

““Model light” = Model light” = Ambient lighting = Ambient lighting = light at cameralight at camera

Light example: main light only

Usually casts Usually casts shadowsshadowsSoft shadow edges Soft shadow edges will depend on main will depend on main light – spotlight, point light – spotlight, point light, directionallight, directional

Light example: added fill light

In real film or In real film or photography, use of photography, use of matte white boards, matte white boards, sheets, umbrellassheets, umbrellasSimilar to ambient Similar to ambient lightinglightingSimulates low-Simulates low-intensity reflection intensity reflection from other surfaces from other surfaces in the scenein the sceneOften no shadowsOften no shadows

Light example: added rim light

Makes a character Makes a character stand out from the stand out from the background, as 3Dbackground, as 3DCan be thought of as Can be thought of as a variation on a fill a variation on a fill lightlight

Light example: added feature light

Lights that only Lights that only interact with the interact with the eyes, to add sparkleeyes, to add sparkleObvious examples in Obvious examples in old black-and-white old black-and-white movies = light movies = light “masks”“masks”Shadows from the Shadows from the environment – environment – window frames, sun window frames, sun through leavesthrough leaves

Variations on the traditional setup

Use sun (directional) light as main lightUse sun (directional) light as main lightFill or rim lights only (film noir look, Fill or rim lights only (film noir look, moonlight)moonlight)Feature lights (eye glitter, eye emphasis)Feature lights (eye glitter, eye emphasis)Ambient plus one main light for simple Ambient plus one main light for simple lightinglighting

Special lighting setups

Instrument up-lighting for dramatic effectsInstrument up-lighting for dramatic effectsHeavenly down-lighting for “aura”Heavenly down-lighting for “aura”Uplighting: evil and/or instrument panelsUplighting: evil and/or instrument panelsBack-lighting for suspense and science fictionBack-lighting for suspense and science fiction““Film noir” minimal lighting, black & whiteFilm noir” minimal lighting, black & whiteOld-fashioned feature lightingOld-fashioned feature lighting““Lens flare” effectsLens flare” effectsGlowsGlowsVolumetric effectsVolumetric effectsImage-projecting lights (colour, stencil/mask)Image-projecting lights (colour, stencil/mask)

Standard lighting : raytracing

Trace rays through virtual monitor from every Trace rays through virtual monitor from every visible surface point back to every lightvisible surface point back to every lightSpotlights count as a cluster of multiple lightsSpotlights count as a cluster of multiple lights

High-tech lighting techniques

Some tecniques more modern than others, Some tecniques more modern than others, particularly in consumer-level softwareparticularly in consumer-level softwareThese lighting techniques often require more These lighting techniques often require more intensive calculations = longer rendering intensive calculations = longer rendering timestimesTrade-off : rendering time vs realismTrade-off : rendering time vs realismLarger studios have massive “render farms”, Larger studios have massive “render farms”, which can consist of hundreds of high-which can consist of hundreds of high-powered computers (often rack-mounted, powered computers (often rack-mounted, with a central control set-up) with a central control set-up)

High-tech lighting : radiosity

Divide surface into Divide surface into patches, energy patches, energy equationsequationsGood for architecture Good for architecture – light equations only – light equations only calculated oncecalculated onceButBut

No transparencyNo transparencyNo mirror reflectivityNo mirror reflectivity

[Sample images from POV-Ray][Sample images from POV-Ray]

High-tech lighting : global illuminationSuperset of raytracing Superset of raytracing and radiosity, attempts and radiosity, attempts to realistically model to realistically model lightinglightingVirtual photons fired Virtual photons fired from light sourcesfrom light sourcesAccumulative light Accumulative light effects, surfaceseffects, surfacesCapable of simulating Capable of simulating reflective and refractive reflective and refractive causticscaustics

[Sample images from POV-Ray][Sample images from POV-Ray]

High-tech lighting : hybrid renderers

Capable of more than one rendering Capable of more than one rendering technologytechnologyRadiosity for matte surfaces, raytracing for Radiosity for matte surfaces, raytracing for relective surfaces, photons for transparent relective surfaces, photons for transparent and refractive surfacesand refractive surfaces

High-tech lighting : area lights

Area lightsArea lightsLight arraysLight arraysGridsGridsDomesDomesSimulate fluorescent lighting, light from Simulate fluorescent lighting, light from ceilings, light from all areas of skyceilings, light from all areas of sky

High-tech lighting : Image-based lighting

An extension of An extension of radiosity, using pixels radiosity, using pixels as luminous patchesas luminous patchesHDRI - High Dynamic HDRI - High Dynamic Range ImagingRange ImagingFloating point colour Floating point colour channels - much more channels - much more than 256 values, than 256 values, including subtle detail including subtle detail in overlit and underlit in overlit and underlit areas.areas.

2D lighting : highlights

As geometryAs geometry

As overlayAs overlay

As effectsAs effectsSparkleSparkleLens flareLens flare

2D lighting : shadows

Shading applied to Shading applied to individual objectsindividual objects

As an effectAs an effectAs geometryAs geometry

Shading applied as Shading applied as an object in blending an object in blending mode (like a 3D mode (like a 3D stencil light)stencil light)Light as “white Light as “white shadow”, blendingshadow”, blending