Motion Capture By: Ali Hosseini. Definition of Motion Capture Motion capture is the recording of...

Motion Capture

By: Ali Hosseini

Definition of Motion Capture

Motion capture is the recording of

human body movement (or other

movement) for immediate or delayed

analysis and playback. “MoCap”

History

• Late 1970’s – Rebecca Allen created the first primitive form of motion capture. “Rotoscoping”

• 1980-1983- Tom Calvert invented “Geniometers”

• 1982-1983- Ginsberg & Maxwell invented “Graphical Marionette”

• 1988- deGraf/Wahrman invented “Mike the Talking Head”

• 1988- Pacific Data Images invented “Waldo C. Graphic”

• 1989- Kleiser- Walczak invented “Dozo”

• 1991- Videosystem invented “Mat the Ghost”

• 1992- SimGraphics invented “Mario”• 1992- Brad deGraph invented

“Alive”• 1993- Acclaim invented two

character animation motion capture

Process of MoCap

• Data needs to be manipulated

• Transform data into file format

• Build specific models

• Attaching the mesh

Questions to Consider

• How many moves in a level?

• Can keyframe techniques be used?

• What process is efficient?

• Budget?

• Knowledge and skill of team?

Preparation Pre-Studio• Spreadsheet breakdown of shots• Diagramming overhead view of action• Story Boards• Floor Plans for desired moves over

large space• Wardrobe, video reference, stunt

support, craft services.

Pre-Shoot List

• Shot list• Move list• Exceptional talent• Food and water

• Talent with comfortable shoes

• A motion capture system and team

• Well rested

Procedure

• Story board drawn up

• Actors positioned at marks

• Director call action

• Operator of MoCap station to start machine

Procedure Cont…

• Game production manager determines best takes.

• MoCap members clean up data• Files are converted into a skeletal

format that is ready for attachment• Skins meet bones

Human Vs. Computer

• MoCap• Quicker Results• Easier to do what

directors wants

• Key framing• Cost effective• Difficult to do what

director wants

Point Weighting & Attachment

• Polygonal characters attached to MoCap data

• Polygonal characters are to be more specific (ex: polygons at elbows, knees, wrist) for maximum flexibility

• Needs to have mesh proportional to bones

• Do attachment right away

Major Problems

• Aggressive moves that need to be stretched and twisted into radical positions tearing and deformation may occur

• Blending Technique stringing all takes

Software Packages for MoCap Data Implementation

• Softimage

• Alias

• 3D Studio Max

3D Studio Max

This software package implements

MoCap data into a PC based Piece of

code

3D Studio Max Plugins

Oxford Metrics • Does well with physique • Has key reduction capabilities to reduce

unwanted data and keep files from balooning

• Allow importation of specified segments of the file and allows moves to blend together with code applied

3D Studio Max Plugins

BioVision

• Called “Motion Manager”

• File format is easy

MoCap Live

Refrences

Sturman, David. “A Brief History of Motion Capture for Computer Character Animation.” 13 March 1999. MEDIALAB. 25 Nov. 2005. http://www.siggraph.org/education/materials/HyperGraph/animation/character_animation

“When Motion Capture Beats Keyframing.” Sept. 1997. Game Developer. http://www.gdmag.com

Kines,Melianthe. “Planning and Directing Motion Capture for Games.” Gecko Interactive.