Motion capture is the process of recording human, animal, or object movement and translating it into a digital 3D model. Rotoscoping, invented in 1915, is considered an early form of motion capture. There are three main types: mechanical, optical, and magnetic. Optical motion capture uses multiple synchronized cameras and markers to track movement. It provides high quality but is expensive and post processing intensive. Magnetic motion capture uses sensors to track movement within a limited range without occlusion issues. Motion capture finds applications in video games, films, animation, education, and biomechanical analysis by enabling realistic animation of characters. While it provides benefits like rapid results, some disadvantages include specialized hardware/software requirements and artifacts from mismatches between the subject and digital

1. MOTION CAPTURE TECHNOLOGY
By
Arundas M.K

2. What is motion capture?
• Motion capture is defined as the process of
recording the movement of humans, animals, and
inanimate objects as 3D data.
• The motion capture is also called Mocap or
Performance capture.

3. History
In 1915 Rotoscoping is invented, by Max Fleischer, this is
considered as start of Motion Capture.
• What is Rotoscoping ?
Rotoscoping is an animation technique in which animators
trace over footage, frame by frame, for use in live-action and
animated films. Originally, recorded live-action film images
were projected onto a frosted glass panel and re-drawn by an
animator. This projection equipment is called a Rotoscope.

4. FRAME BY FRAME TRACING OF AN OBJECT
(ROTOSCOPING)

5. CLASSIFICATION OF MOTION CAPTURE
Generally motion capture can be classified into three
categories :
1. Mechanical motion capture
2. The optical motion capture
3. The magnetic motion capture

6. 1. MECHANICAL MOTION CAPTURE
o Mechanical motion capture systems directly track body
joint angles and are often referred to as exo-skeleton
motion capture systems.
o The sensors are attached to the body of performer and
each joints are connected to the angular encoder.
o The value of movement of each encoder (rotation etc..)
rebuild by a computer that by knowing the relative
position encoder can rebuild the movement on the
screen using software
o Mechanical motion capture systems are real-time
system.

9. Advantages
 Offer high precision
 Do not depend on external factors such as no. of
cameras
 Computes rotations directly
 Portable, unlimited range
 Less expensive
 Can capture multiple performances simultaneously
 No built in positional reference

10. Disadvantages
 External structure unwieldy
 Cannot change the configuration, i.e., a
hand capture can’t be used for an arm
 It is complicated to measure the
interaction of several exoskeletons.

11. 2.The Optical Motion Capture
o The capture is based on optical
shooting several synchronized
cameras
o 2to 32 cameras controls by computer
o Operating principle is similar to radar

13. Working Principle
The cameras emits the
radiation (usually infra red), reflected by the
markers(whose surface is reflected by ultra reflecting
material) and then returned to same cameras. These are
sensitive to one type of wave length and viewing markers in
the form of white spot videos. Checking the information of
each camera to determine the position of markers in virtual
space.

15. Advantages
 Freedom of movement
 High quality capture
 High throughput
 fast sampling (200 fps at a high
resolution)
 can capture fast motions
 can have a large capture space
 can capture many markers

16. Disadvantages
• Occlusion, markers are can be hidden from the camera
1. additional performers will increase occlusion
2. may be able to add redundant cameras
• Marker crossover, which marker are you looking at?
• It is more expensive
• Extensive post processing (the marker’s have to be located and
identified

17. 3.THE MAGNETIC MOTION CAPTURE
 Performer wears an array of magnetic receivers which track location with
respect to transmitter
 Derived from the sensors placed on military aircraft pilots helmet to track the
pilot head position and orientation for the helmet-mounted display.
 12-20 tracking sensors are placed on a captured subject.
 Tracking sensors output their translation and orientations.
 Divide into two groups
1. Direct Currant (DC) : Uses square pulses
2. Alternating Currant (AC) : Uses sin wave pulse

18. Advantage
• No occlusion
• Less expensive than optical motion
capture

19. DISADVANTAGES
Limited range
Sensitivity to metals
Cannot perform with multiple actors
Capture volume is limited

20. Applications Of Motion
Capture
• Video Games
• Film / Animation
• Education
• Biomechanical analysis etc..

21. Video Games
Video games often use motion
capture to animate athletes,
martial artists, and other in-
game characters.

22.  Generally there are two main types of 3D character animation used in games:
1. Real-time playback
2. Cinematics
 Real-time allows the game player to choose from pre-created moves, thus controlling
the character's moves in real-time.
 Cinematics are the fully rendered 'movies' used for intros and 'cut-scenes'. Often the last
part of game production, or a process that is sub-contracted to a separate studio.
 Cinematics are generally not essential to game-play, but do add a lot of appeal to the
game, and help immensely with story development and mood generation.

23. Film/Animations
 Motion capture is being used more and more in films
nowadays
 Motion capture based animation is essential for
creating characters that move realistically, in
situations that would be impractical or too dangerous
for real actors
 Some film characters require the use of motion
capture, otherwise their animation seems fake
 Films that used motion capture technologies are
Avatar, The adventures of tintin, The avangers,
Hulk, Iron man, Kochadaiiyaan etc…

24. Avatar Is The One Of The Best Film Ever Used The
Motion Capture Technology

25.  In this film photorealistic computer-generated characters,
created using motion-capture animation technology
 To achieve the face expressions, actors wore individually
made skull caps fitted with a tiny camera positioned in
front of the actors' faces
 This method allows the filmmakers to transfer 100% of the
actors' physical performances to their digital counterparts

26.  Education
Motion capture training can make a huge difference in an animators training. While
access to motion capture is not a substitute for developing good art skills and good
traditional character animation abilities, it can go a long way towards making someone
more employable.
 Biomechanical analysis
Biomechanical analysis for rehabilitation purposes, relies extensively on motion
capture, for its ability to produce repeatable results. Motion capture can be used to
measure the extent of a client's disability as well as a client's progress with
rehabilitation.
This technology also applicable in scientific research, engineering fields etc…

27. Advantages Of Motion
Capture
 More rapid, even real time results can be obtained. In entertainment applications this
can reduce the costs of keyframe-based animation
 The amount of work does not vary with the complexity or length of the performance
to the same degree as when using traditional techniques
 Complex movement and realistic physical interactions such as secondary motions,
weight and exchange of forces can be easily recreated in a physically accurate
manner
 The amount of animation data that can be produced within a given time is extremely
large when compared to traditional animation techniques
 Potential for free software and third party solutions reducing its costs.

28. Disadvantages
 Specific hardware and special software programs are
required to obtain and process the data.
 The cost of the software, equipment and personnel
required can be prohibitive for small productions.
 The capture system may have specific requirements
for the space it is operated in, depending on camera
field of view or magnetic distortion
 Movement that does not follow the laws of physics
cannot be captured.
 If the computer model has different proportions
from the capture subject, artifacts may occur. For
example, if a cartoon character has large, over-sized
hands, these may intersect the character's body if the
human performer is not careful with their physical
motion.

29. THANK YOU….