MUL242 3d modelling + animation

1. MUL242 3d modelling + animation 07 Rendering

2. this lecture... this lecture will look at... • Rendering • what is it? • rendering models • Bringing it Together • Models • Surfaces • Animation • Sound • Lighting • Cameras • Project Management

3. rendering • the rendering process involves giving objects shading via a number of different methods • each pixel is rendered by considering the interaction of an objects surfaces and light sources to derive its colour • colour images are typically 32bit, greyscale are 8bit... • the time taken to calculate the image is the same • the memory requirement is less in greyscale • 32bit rendered images include an 8bit alpha channel • 24bits colour + alpha channel for matting/compositing • rendering algorithms are procedures used by a particular program to generate an image from the view of a modelled world

4. rendering 24 bits (8+8+8 RGB) + 8 bits (Alpha) = 32 bits. Think of the possibilities!

5. ray casting • the colour of each pixel is typically calculated using a process called ray-casting • the ray casting algorithm casts a single ray through each pixel. If the ray strikes a surface, the colour of the surface is calculated and assigned to the pixel but... how is colour calculated?

6. shading models • shading models work in tandem with raycasting renderers to calculate the shading of a particular point on a surface and to determine the colour of a pixel based upon… • lights in a space • light shining on objects • light bouncing on objects from other objects • shading of objects based upon their surface properties • all shading models are approximations… the better the approximation… the better the image… and the longer it takes to render

7. shading models • faceted shading • uses the assumption that a surface is the same colour across its entire face • colour is calculated by using the surface normal to determine the direction of the surface relative to lighting • surfaces facing a light are brighter than those facing away • using the surface normal, flat surfaces render OK but curved surfaces require many normals in order for a correct approximation to take place • Bezier-based modellers convert curved surfaces into patches in order to render using facets

8. smooth shading • smooth shading algorithms take the change in surface normals across a surface into account • Gouraud shading (Henri Gouraud) • process... • calculates the average surface normal at each vertex • uses the average to calculate a colour at each vertex • interpolates colour between corners • produces good shading but generates a polygonal structure at the edges

9. smooth shading • Phong shading (Bui Tuong Phong) • calculates the average surface normal at each vertex • uses the average to interpolate surface normals across a surface • interpolates colour between the new normals across a surface • generates much better images than Gouraud but also takes longer • raycasting algorithms have a major limitation in that they only deal with every object in a scene as if it existed in isolation. • casting shadows, transparency and reflection are all effects that require the effect of multiple objects to be calculated

10. ray tracing • ray tracing takes into account all objects in a scene simultaneously by more accurately simulating the real world… • a specific point on a surface is affected by light falling onto the surface from the environment via reflection… many light rays affect every point on a surface.

11. ray tracing • ray tracing traces the rays of light backward through a model to determine how the image should appear • if the light ray comes from a surface, the renderer then calculates where the light that reflected off that surface originated and hence all the objects which it bounced off or passed through. • eg. the colour of the cylinder is influenced by the colour of the cube, the cone and the space around the cube

12. ray tracing • can render almost any effect, true reflectivity, refractive transparency and shadows • very computationally expensive...but results are brilliant • problems… • shadows are sharp • diffuse reflection of light between surfaces • eg. holding a red card in front of a white wall should cause a pink hue to appear on the wall • radiosity does this but is REALLY SLLLOOOOWWW!!!

13. Radiosity & Caustics • Diffuse reflected light is referred to in CG terminology as radiosity. • light coming from any source will touch a surface of some kind, then part of that light will reflect away, perhaps touching another surface and reflecting again.

14. Caustics • Caustics is the focusing of light due to reflection or refraction onto another surface so as to cause areas of intense illumination.

15. bringing it all together • 3D development is a collaborative venture involving: • Project Managers • Scriptwriters • Graphic Designers • 3D artists: • Modellers • Surface artists • Lighting Designers • Cinematographers • Animators

16. SHREK - Technical Credits • Production Design by • James Hegedus   • Art Direction by • Guillaume Aretos (II)   • Douglas Rogers   • Costume Design by • Isis Mussenden   • Production Management • Mitchell Ferm .... production supervisor for technology • Kate Swanborg .... production manager: Los Angeles preproduction • Triva von Klark .... production manager • Art Department • Craig Edelblut .... set designer • Raman Hui .... character designer • Bill Perkins (II) .... development artist • Tom Sito .... storyboard artist • Sound Department • Anna Behlmer .... sound re-recording mixer • Lon Bender .... supervising sound editor • Valerie Davidson .... sound editor • Scott Martin Gershin .... sound designer • Kevin Globerman .... second engineer (uncredited) • Craig Heath .... sound recordist (as Craig "Pup" Heath) • Tony Lamberti .... sound effects editor • Jennifer L. Mann .... foley editor • Alan Meyerson .... music scoring mixer • Andy Nelson (I) .... sound re-recording mixer • Robert Renga .... sound recordist • Brian Richards (II) .... music editor • Charleen Richards .... adr mixer • Gregg Silk .... second engineer (uncredited) • Carlos Sotolongo .... original dialog mixer • Wylie Stateman .... supervising sound editor

17. SHREK - Technical Credits (cont) • Hugh Waddell .... adr supervisor • Wade Wilson (II) .... sound designer & co-supervisor: 2002 Imax re-release version • sound designer & editor • Visual Effects by • Victoria Alonso .... senior unit production manager: Los Angeles preproduction • Ken Bielenberg .... visual effects supervisor • Christian Cunningham .... technical director • Nickson Fong .... digital artist: Dreamworks SKG, LA crew • Ben Gunsberger .... lighting animator • Albert Hastings .... digital layout/character setup • Lee Lanier .... digital artist • Bert Poole .... digital artist: Senior Lighting Animator • Bill Seneshen .... effects lead: cloth simulation • Susan Thayer .... digital artist: additional effects • Carlos A. Vidal .... digital artist: senior technical director • Other crew • John Bell (II) .... orchestrator • Andrew Birch .... post-production coordinator • Steve Bloom (II) .... additional editor • Liz Borges-Herzog .... receptionist • Randy Cartwright .... story supervisor • Toby Chu .... music assistant • John A. Coleman .... orchestrator • Cassidy Curtis .... character technical director • Anthony Domingo .... hardware engineer: production support • Elizabeth Finch .... orchestrator • Bruce Fowler (I) .... orchestrator • Walt Fowler .... orchestrator • John Garbett .... pre-production: Los Angeles • Philip R. Garrett .... production assistant (uncredited) • Matthew Goodman .... post-production supervisor: International release (uncredited) • Rex Grignon .... animator • Mo Henry .... negative cutter • Tom Hester .... character designer • Anthony Hodgson .... animator

18. SHREK - Technical Credits (cont) • Raman Hui .... supervising animator • Ethan Hurd .... animator • Danny Jacobs (II) .... musician: guitar • Christopher Knights .... first assistant film editor • Boris Kossmehl .... animator • Eric Lessard .... animator • Philip K. Livingston Jr. .... production assistant • Ladd McIntosh .... orchestrator • Walling C. Michael .... render wrangler • Marc Miller (V) .... render assistant • Yvonne S. Moriarty .... orchestrator • Christine M. Norton .... assistant to producer • Jessica Nourse .... singing voice: Cameron Diaz • Elisa Pensler-Gabrielli .... adr loop group • Emmanuel Roth .... animator • Steven Sorensen (III) .... render assistant • Allen Stetson .... render assistant • Drew Stewart .... production assistant • James C.J. Williams .... title designer: end titles • Hans Zimmer .... special thanks Jobs include: • Set Designers • Storyboard Artists • Clothing Designers • ‘Render Wrangers’!

19. Project Management • Essential to Successful Completion of any large Multimedia project • Need to Monitor allocation of resources: • Time • Budget • Talent • Need to Promote: • Communication • Collaboration • Creativity

20. Workshop • Surfacing • Rendering • Rule of thirds • Camera zoom • Motion blur • Depth of field • Assignment workshop