Upload
gerald-fowler
View
217
Download
0
Tags:
Embed Size (px)
Citation preview
Business and Computing Deanery
Multimedia
Week 20 Lighting
Multimedia 2
Last week Animation Cameras Video
Streaming Compression Production
Multimedia 3
This week Realtime and photorealistic Rendering Lighting concepts Types of lighting Shadows
Multimedia 4
Realtime v. photorealistic Compare lighting
OpenGL - max 8 Photorealistic – 10 per character
Convergence of realtime and photorealistic Realtime is now used to plan real
movies Used extensively in games
Multimedia 5
Internalor3rd party
Traditional
The CG production pipelineStory
Art
Set design Layout Animation Shading
Modelling
Rendering
Lighting Simulation Effects
Film
Commercial
Editorial
Multimedia 6
Rendering The act of translating the information in
the files that make up the shot into a single frame of film
Rendering "fills in" geometry with color, shadow, lighting effects, etc.
Pixar have created Renderman 10 years ago it took 6 hours to render one
frame How many today?
Use render farms
Multimedia 7
Concepts Light has warmth (yellowish) or
coolness (bluish) Intensity Angle if incidence Radiosity
Light reflecting from an object Attenuation
Light becomes weaker with distance3ds max v7
Multimedia 8
Lighting basics Three main sources of lighting in
classic photography Key Fill Backlight
Concepts apply to 3D programs, plus Ambient light
Multimedia 9
Getting it right
3ds max v7
Multimedia 10
Key light Outdoors
The sun Indoors
Major window Main electric light Flash on a camera Spot light on a stage
Multimedia 11
Fill and key lights Fills in the dark shadows
cast by the key light Outdoors may be created
artificially Indoors from secondary
lights Distant window Light fitting
Softens shadows 3ds max v7
Multimedia 12
Backlight Situated behind the subject Separates the foreground from the
background Can make the scene more three-
dimensional
Multimedia 13
Lighting strategies
3ds max v7
Multimedia 14
Planning lighting Default lighting Use this until you are happy with the
scene, then add lights Use as few as possible Start with the key light
Maybe a spot Add fill
Use omni or several spots Finally add accent lighting
3ds max v7
Multimedia 15
Ambient light Not a light source
Light from other sources bouncing of walls, the ceiling and other objects in the scene
3ds max v7
Multimedia 16
Types of lighting Standard
Spotlights Omnidirectional light Directional light
Advanced Photometric lights
Multimedia 17
Spotlights Casts a focused beam of light like a
flashlight, a follow spot in a theatre, or a car headlight
3ds max v7
Multimedia 18
Omnidirectional light Known as omni light Like a bare light bulb Casts rays in all directions from a
single source
3ds max v7
Multimedia 19
Directional light Also known as Distant lights Cast parallel light rays Primarily used to simulate sunlight
Multimedia 20
Target lights Concept like cameras Target
Easier to aim Simply position the target object at
the centre of interest Free
3ds max v7
Multimedia 21
Lighting directionSingle light from side Single light straight on
Both sides Reduced full fill
3ds max v7
Multimedia 22
Activity Open up your model of a room, save
with a new file namse Add one or more spotlights to
provide lighting and render the scene Experiment with moving them around
and rendering the effect Add an omni light behind the scene Alter the values to achieve a
balanced rendering
Multimedia 23
Standard light settings Intensity Angle of incidence Attenuation Reflected light and ambient light Colour
Multimedia 24
Attenuation Natural reduction
of light intensity
3ds max v7
Multimedia 25
Brightness and colour Intensity sets the brightness of the
scene Range from 0 to 255 (white) Colour – use the RGB sliders
3ds max v7
Multimedia 26
Activity With your scene experiment with
your light settings Vary the light settings for:
Intensity Angle of incidence Attenuation Reflected light and ambient light Colour
Multimedia 27
Use of shadows
Default lighting
Spot plus low level back lighting
Spot
3ds max v7
Multimedia 28
Shadows Photometric and standard lights
both have the same options for generating shadows
Two types Shadow mapped Ray-traced
Multimedia 29
Shadow mapped Grayscaled texture map based on the
lighting and mesh Soft-edged More natural May be blocky May be inaccurate May be incorrectly positioned Do not take transparency into account Do not take on the colour cast of the
object May use a lot of RAM 3ds max v7
Multimedia 30
Ray traced shadows Ray tracing
techniques Have a hard edge
Software can be used to soften
Very accurate and precise
Does not use a lot of RAM 3ds max v7
Multimedia 31
Hotspot and falloff Hotspot
Angle of the inner portion of the beam
Falloff Angle of the outer
beam Differences in
angles make the effect softer
3ds max v7
Multimedia 32
Include and exclude Some software allows you to set up
lights that affect only certain objects Use a pick list to select objects
Multimedia 33
Colour and mood Cool colours – blues and violets
Still and calm Warm colours – yellows, red and
orange Fiery and energetic Intense and active
Be careful, keep it subtle
Multimedia 34
Activity Create a flat surface with a sphere
and a cone sitting on top Add a spot light Add a fill light
Alter the hotspot/fallout Alter the type of shadow
Multimedia 35
Photometric lights Photometric lights
enable you to more accurately define lights as they would be in the real world using ray tracing
Distribution, intensity, colour temperature can be set 3ds max v7
Multimedia 36
Global Illumination with Radiosity Standard lights are simpler than
natural lighting Using photometric lights with a
radiosity solution with your lights provides a better model of the real world
Radiosity is rendering technology that realistically simulates the way in which light interacts in an environment
Multimedia 37
Preset photometric lights Generic 60W Bulb Generic 75W Bulb Generic 100W Bulb Generic Halogen Spotlight Generic Recessed 75W Lamp (web) Generic Recessed 75W Wallwash (web) Generic Recessed 250W Wallwash (web) Generic 4ft Pendant Fluorescent (web) Generic 4ft Cove Fluorescent (web) Generic Street 400W Lamp (web) Generic Stadium 100W Lamp (web)
Multimedia 38
Photometric lights Target Point
Similar to a standard omni light, emits light from a geometric point
Spotlight Focused beam
Web distribution Distribution of light Many lighting manufacturers provide
web files that model their products 3ds max v7
Multimedia 39
Sunlight and Daylight A system that follows the
geographically correct angle and movement of the sun over the earth at a given location
You can choose Location Date and time Compass orientation.
3ds max v7
Multimedia 40
Daylight Daylight combines sunlight and
skylight The sunlight component can be either IES Sun light
Illuminating Engineering Society Values set automatically based on geographic
location, time, and date Or a standard light (a target direct light).
The sky component can be either an IES Sky light Or a Skylight.
Multimedia 41
Self assessment You have been asked to model a
lecture theatre for Hope Compare and contrast the lighting
required for A guest lecture without note taking A lecture with note taking and
discussion sessions
Multimedia 42
For Next Week Submit your Portfolio 2.2 Work on the 3ds max tutorials Directed reading chapter 6 and 10
Giambruno M, (2002) 3D Graphics & Animation, 2nd Edition
Multimedia 43
References Giambruno M, (2002) 3D Graphics & Animation,
2nd Edition, New Riders, ISBN: 0-7357-1243-3 Kerlow I. V., (2003) The Art of 3-D Computer
Animation and Effects , 3rd Edition, John Wiley & Sons Inc; ISBN: 0471430366
Murdock K.L., (2005) 3DS Max 7 Bible, John Wiley & Sons Inc, ISBN: 0764579711
Screen shots taken from 3ds max 7 User Reference