Compositing, composing worlds Nelson Zagalo, University of Minho, Portugal

Universidade do Minho

13th May 2011, University of Maribor, Slovenia

Nelson Zagalo Contact me nzagalo@ics.uminho.pt www.facebook.com/nelsonzagalo My Work nelsonzagalo.googlepages.com www.engagelab.org

King Kong (1933) Superman (1978)

Film Compositing

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.

Defining compositing

What 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.

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

Compositing techniques

F1. Physical - Glass, Statues, Paintings

The Fiendish Plot of Dr. Fu Manchu (1980)

Clash of the Titans (1981)

F2. Multiple exposure

L´Homme Orchestre, George Melies, 1900

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

video

F3. Background projection

Sunset Boulevard, 1950

2001, Space Odyssey, 1968

North by Northwest, 1959

The Birds, 1963

F4. Matting

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

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

Digital Advantages

video

D1. Blend Operations

Multiply

Screen

Overlay

Darken

Lighten

Difference

Exclusion

Luminosity

D1. Blend Operations

D2. Keying

AE: Color Key, Edge Thin, Color Tolerance, Luma Key, Matte Choker

Edge Thin

Color Key

Matte Choker

Luma Key

Color Tolerance

D2. Keying

The Chronicles of Narnia (2005)

King Kong (2005)

D2. Keying

The Saint (1997)

Preserve reflexes

D3. Alpha

32-bit image carries a fourth Alpha channel that stores transparency (or alpha) data. The alpha channel’s 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. Matte

Luma Mattes External 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

feathered mattes

solid 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 Correction

Color 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 Correction

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

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

High Dynamic Range images

Before After

D7. Nesting and Parenting

Nesting – means building compositions and put them inside other compositions.

nesting

D7. Nesting and Parenting

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

Parenting

Parenting - permits the association or control of animation settings through different layers.

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

D8. Motion track and match moving

Motion 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.

2d Tracking – track objects only 3d Tracking – track camera position Can be done in After Effects. It’s different from Parenting in the sense that parenting only synchronizes layers, albeit Tracking synchronizes content within the image.

video video

It 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.

D8. Motion track and match moving

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 References Leow 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-matte-painter-portrait-of.html

Nelson Zagalo nelsonzagalo.googlepages.com engagelab.org

Compositing, composing worlds

Universidade do Minho