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.
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.
7.
8.
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
12.
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.
14.
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
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.