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3D Modelling Tools

3D Modelling Tools. Week 16 – Lighting. This week. Lecture Lighting Rendering Computer graphics Standard lights Shadows 3DS Max 7 Bible Chapter 27. Rendering. Rendering "fills in" geometry with color, shadow, lighting effects, etc.

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3D Modelling Tools

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  1. 3D Modelling Tools Week 16 – Lighting

  2. This week Lecture • Lighting • Rendering • Computer graphics • Standard lights • Shadows • 3DS Max 7 Bible • Chapter 27 3D Modelling Tools

  3. Rendering • Rendering "fills in" geometry with color, shadow, lighting effects, etc. • Converts three dimensional scenes to two dimensional screens by following rays of light from the eye of the observer to a light source 3D Modelling Tools

  4. Photorealistic rendering • “In computer graphics, photorealistic rendering attempts to make artificial images of simulated 3d environments that look just like the real world.” • Reynolds (2003) • Where is it used? • What are the implications? • Hardware • Time • Interactivity 3D Modelling Tools

  5. Realtime rendering • Relies on graphics cards with 3D hardware accelerators • Where is it used? • What are the implications? • Hardware? • Time • Interactivity 3D Modelling Tools

  6. Rendering techniques 1 • Ray casting • Renders the scene as observed from a specific point-of-view based only on geometry using very basic optical laws of reflection intensity • Does not render accurately reflections, refractions, or the natural fall off of shadows 3D Modelling Tools

  7. Rendering techniques 2 • Ray tracing • Similar to ray casting, but employs more advanced optical simulation • Can use multiple rays • Traced through a number of sequential 'bounces‘ • Realistic reflections and shadows • Too slow to consider for realtime 3ds max v7 3D Modelling Tools

  8. Rendering techniques 3 • Radiosity • Uses finite element mathematics to simulate diffuse spreading of light from surfaces • Rendering technology that realistically simulates the way in which light interacts in an environment 3ds max v7 3D Modelling Tools

  9. Comparison 3ds max v7 3D Modelling Tools

  10. Render farms • Rendering networks are sometimes called “render farms.” • In the software, one computer is set up as the network Manager. • The Manager "farms out" or distributes the work to rendering Servers. • Pixar have created Renderman • 10 years ago it took 6 hours to render one frame • How many today? • Use render farms 3D Modelling Tools

  11. Lighting - realtime v. photorealistic • Compare lighting • OpenGL - max 8 lights • Photorealistic – 10 lights per character • Convergence of realtime and photorealistic • Realtime is now used to plan real movies • Used extensively in games 3D Modelling Tools

  12. The CG production pipeline Traditional Story Editorial Art Internal or 3rd party Modelling Set design Layout Animation Shading Lighting Simulation Effects Commercial Rendering Film 3D Modelling Tools

  13. Concepts • Light has warmth (yellowish) or coolness (bluish) • Intensity • Angle if incidence • Radiosity • Light reflecting from an object • Attenuation • Light becomes weaker with distance 3ds max v7 3D Modelling Tools

  14. Lighting basics • Three main sources of lighting in classic photography • Key • Fill • Backlight • Concepts apply to 3D programs, plus • Ambient light 3D Modelling Tools

  15. Getting it right 3ds max v7 3D Modelling Tools

  16. Key light • Outdoors • The sun • Indoors • Major window • Main electric light • Flash on a camera • Spot light on a stage 3D Modelling Tools

  17. 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 3D Modelling Tools

  18. Backlight • Situated behind the subject • Separates the foreground from the background • Can make the scene more three-dimensional 3D Modelling Tools

  19. Lighting strategies 3ds max v7 3D Modelling Tools

  20. 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 3D Modelling Tools

  21. Ambient light • Not a light source • Light from other sources bouncing of walls, the ceiling and other objects in the scene 3ds max v7 3D Modelling Tools

  22. Types of lighting • Standard • Spotlights • Omnidirectional light • Directional light • Advanced • Photometric lights 3D Modelling Tools

  23. Spotlights • Casts a focused beam of light like a flashlight, a follow spot in a theatre, or a car headlight 3ds max v7 3D Modelling Tools

  24. Omnidirectional light • Known as omni light • Like a bare light bulb • Casts rays in all directions from a single source 3ds max v7 3D Modelling Tools

  25. Directional light • Also known as Distant lights • Cast parallel light rays • Primarily used to simulate sunlight 3D Modelling Tools

  26. Target lights • Concept like cameras • Target • Easier to aim • Simply position the target object at the centre of interest • Free 3ds max v7 3D Modelling Tools

  27. Lighting direction Single light from side Single light straight on Both sides Reduced full fill 3ds max v7 3D Modelling Tools

  28. Activity • Create a flat surface with a sphere and a cone sitting on top • 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 3D Modelling Tools

  29. Standard light settings • Intensity • Angle of incidence • Attenuation • Reflected light and ambient light • Colour 3D Modelling Tools

  30. Attenuation • Natural reduction of light intensity 3ds max v7 3D Modelling Tools

  31. Brightness and colour • Intensity sets the brightness of the scene • Range from 0 to 255 (white) • Colour – use the RGB sliders 3ds max v7 3D Modelling Tools

  32. 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 3D Modelling Tools

  33. Use of shadows Default lighting Spot 3ds max v7 Spot plus low level back lighting 3D Modelling Tools

  34. Shadows • Photometric and standard lights both have the same options for generating shadows • Two types • Shadow mapped • Ray-traced 3D Modelling Tools

  35. 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 3D Modelling Tools

  36. 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 3D Modelling Tools

  37. 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 3D Modelling Tools

  38. Include and exclude • Some software allows you to set up lights that affect only certain objects • Use a pick list to select objects 3D Modelling Tools

  39. 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 3D Modelling Tools

  40. 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 3D Modelling Tools

  41. 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 3D Modelling Tools

  42. 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 3D Modelling Tools

  43. 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) 3D Modelling Tools

  44. 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 3D Modelling Tools

  45. 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 3D Modelling Tools

  46. 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. 3D Modelling Tools

  47. Portfolio 9 • Create a model with a cone, sphere and tube sitting on a flat surface with lighting to show: • Strong directional lighting, similar to on a stage • A general well lit scene • Produce 2 A4 sheets, one for each scene containing a small rendering of the scene and an annotated plan showing and describing the lights used 3D Modelling Tools

  48. Questions • List and describe three different light types used in 3D modelling giving their parameters and examples of their use • Describe, giving light types, parameters and positions how you would light a scene: • A stage • A well lit indoor room • A darkened room light by a candle • Consider how this might be done as a storyboard • Discuss the difficulties in including shadows within games 3D Modelling Tools

  49. Impendent study • Directed reading 3DS Max 7 Bible • Read Chapters 27 • Portfolio 9 • Tutorials • Introduction to Lighting 3D Modelling Tools

  50. References • 3ds max v7, (2005) User Reference and Tutorials • Murdock K.L., (2005) 3DS Max 7 Bible, John Wiley & Sons Inc, ISBN: 0764579711 • Reynolds C., (2003) Stylized Depiction: Non-Photorealistic, Painterly and 'Toon Rendering, http://www.red3d.com/cwr/npr/ accessed 09/01/2007 3D Modelling Tools

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