compositing, composing worlds

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Course on Digital Compositing lectured at University of Maribor, Slovenia.

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Universidade do Minho

Compositing, composing worldsNelson Zagalo, University of Minho, Portugal

13th May 2011, University of Maribor, Slovenia

Nelson ZagaloContact me

nzagalo@ics.uminho.pt www.facebook.com/nelsonzagalo

My Work

nelsonzagalo.googlepages.com www.engagelab.org

Film Compositing

King Kong (1933)

Superman (1978)

Defining compositingWhat is it? Compositing is the combining of visual elements from separate sources into single images, often to create the illusion that all those elements are parts of the same scene.

What do we use it for? . to create special effects in visual arts; . to help us connecting real images with artificially created ones; . to correct photographic mismatches (e.g. color); . to change or substitute backgrounds; . to change or substitute foregrounds; . to create illusion of depth.

Compositing techniques

Film (analogical) 1. Physical compositing 2. Multiple exposure 3. Rear projection 4. Matting Digital 1. Blend Operations 2. Keying 3. Alpha Channels 4. Mattes 5. Masks 6. Nesting 7. Color Correction 3d Compositing 8. Motion tracking and match moving

F1. Physical - Glass, Statues, PaintingsThe Fiendish Plot of Dr. Fu Manchu (1980)

Clash of the Titans (1981)

F2. Multiple exposureMultiple exposure of Alfred Hitchcock directing during rehearsals for Shadow of a Doubt (1943).

video

LHomme Orchestre, George Melies, 1900

F3. Background projection

North by Northwest, 1959

2001, Space Odyssey, 1968

Sunset Boulevard, 1950

F4. MattingThe Birds, 1963

video

Compositing techniques

Film (analogical) 1. Physical compositing 2. Multiple exposure 3. Rear projection 4. Matting Digital 1. Blend Operations 2. Keying 3. Alpha Channels 4. Mattes 5. Masks 6. Nesting 7. Color Correction 3d Compositing 8. Motion tracking and match moving

Digital Advantagesvideo

Omaha beach scene making of, belonging to the BBC series Timewatch: Bloody Omaha. Created by Colin Thornton, Neil Wilson and Steven Flynn from Compost Creative. 3 persons + 4 days + 1 camera + pop up greenscreen + after effects

D1. Blend Operations

Multiply Screen Overlay Darken Lighten Difference Exclusion Luminosity

D1. Blend Operations

D2. KeyingAE: Color Key, Edge Thin, Color Tolerance, Luma Key, Matte Choker

Color Key Luma Key

Edge Thin

Color Tolerance Matte Choker

D2. KeyingThe Chronicles of Narnia (2005)

King Kong (2005)

D2. KeyingPreserve reflexes

The Saint (1997)

D3. Alpha

32-bit image carries a fourth Alpha channel that stores transparency (or alpha) data. The alpha channels 8-bit data is reserved to give an image or video clip shape and transparency when composited. Software as Photoshop creates content on transparent backgrounds retaining background transparency when imported into motion applications. This is because an alpha channel matte is automatically generated.

Object on transparency

Alpha Channel

Final composition

D3. Alpha

D4. MatteLuma MattesExternal image that is used to make portions of another image transparent. Luminance mattes should not be confused with alpha mattes, which are internal mattes that are derived from alpha channels. Both alpha channel mattes and luminance mattes can be composed of solid shapes, feathered shapes, gradients, typography, entire images. luma mattes

solid mattes

feathered mattes

D4. Matte

video

D5. Masks

Masks are defined by splines - paths that consist of interconnected points that form a line segment or curve, around the subject, an art also knoww as Rotoscoping. Masks can be animated.

D5. Masks

Forrest Gump (1994)

video

D6. Digital Color CorrectionColor grading is the process of altering and enhancing the color of a motion picture, television image, or still image either electronically, photo-chemically or digitally.

D6. Color CorrectionHigh Dynamic Range images

Before

After

High Dynamic Range images (HDRi) are a set of techniques that allow a greater dynamic range of luminance between the lightest and darkest areas of an image than current standard digital imaging techniques or photographic methods

Mente Magica - http://mentemagica.com/wp/2009/12/31/hdr-reactor/

D7. Nesting and ParentingNesting means building compositions and put them inside other compositions.

nesting

D7. Nesting and ParentingParenting - permits the association or control of animation settings through different layers.video

ParentingFrom Animated type tutorial 3: anchor points and parenting, by Gareth Smith, http://vimeo.com/22582326

Compositing techniques

Film (analogical) 1. Physical compositing 2. Multiple exposure 3. Rear projection 4. Matting Digital 1. Blend Operations 2. Keying 3. Alpha Channels 4. Mattes 5. Masks 6. Nesting 7. Color Correction 3d Compositing 8. Motion tracking and match moving

D8. Motion track and match movingMotion tracking and Match moving, are techniques that allow the insertion of computer graphics into live-action footage with correct position, scale, orientation, and motion relative to the photographed objects in the shot.video video

2d Tracking track objects only Can be done in After Effects. Its different from Parenting in the sense that parenting only synchronizes layers, albeit Tracking synchronizes content within the image.

3d Tracking track camera position

D8. Motion track and match movingIt is not related with motion capture, and needs special software as Boujou or NukeX to extrapolate three-dimensional information from two-dimensional photography. Tracking information is then transferred to computer graphics software such as Cinema 4d, 3ds Max or Maya and used to animate virtual cameras and CGI objects.video video

D8. Match moving

video

Compositing break down for "The Third & The Seventh", a short-film entirely modeled in 3d, which has gone through intense compositing.

Bibliography Ron Brinkman, Art & Science of Digital Compositing, Morgan Kaufmann, 2008 Richard Rickitt, Special Effects: The History and Technique, Billboard Books, 2007 Krasner, J., Motion Graphic Design: applied history and aesthetics, Elsevier, 2008

ReferencesLeow Wee Kheng, Digital Compositing, CS5245 Vision and Graphics for Special Effects, National University of Singapore, www.comp.nus.edu.sg/~cs5245/lecture/compositing.pdf Matte Shot - a tribute to Golden Era special fx - http://nzpetesmatteshot.blogspot.com/2010/11/leigh-took-mattepainter-portrait-of.html

Universidade do Minho

Compositing, composing worlds

Nelson Zagalonelsonzagalo.googlepages.com engagelab.org