athletes. For example, principle of optics can be
used for capturing the three-dimensional motion of
athletes. The theory is to stall multiple different
optical cameras and ask the athlete to wear motion
clothing with optical radiation. Motion capture
system will convert the pictures it captured into
three-dimensional coordinates, which will be later
connects to the anatomic points of human body
model created by computer. Or the computer could
be used to calculate the connecting parts or rotating
parts which could be converted into animation. By
using the functions of materials and textures of
animation software such as MAYA, motions
captured by those three-dimension coordinates are
just like real motions.
4 DEVELOPMENT OF 3D
ENGINE FOR SYSTEM
SOFTWARE OF SIMULATION
SYSTEM FOR VR PHYSICAL
EDUCATION
As the most important platform in game
development, 3D engine can design very realistic
virtual environment, because it has the function of
lighting effects. In addition, 3D engine can provide
powerful physical environment for the system,
making the virtual system more realistic and natural.
Last but not least, as a development platform in
common use for simulation software, the system can
provide human-computer interaction, making the
athletes study better. And the most important
technology to realize the interaction is about objects
picked and dragged by the mouse. The fundamental
principle is to control the 3D scene by controlling
the movement of the mouse in 2D screen.
5 SIMULATION MODELING OF
VIRTUAL TEACHING SYSTEM
5.1 The Establishment of Human Body
Model
To establish human body model, digital human
skeleton model should be used to stratify the
building of human body model, dividing the main
skeleton into body joints, bones and center of gravity
of human body (Zhan Shengli, 2006). The virtual
human model has virtual skeleton and the surface
model (skin, fine wrinkles, etc.) of surface human.
Therefore, it stratifies the virtual human model into
two layers: skeleton and different parts. Surface
model has 53 pieces of different sizes. Those pieces
form public areas between parts where there is no
double connection. Every part rotates around its
joint, which result into different postures, making
the digital virtual human movements even more
realistic and perfect.
5.2 Modeling of System Software of
Simulation System for VR Physical
Education
Simulation technology using the computer is crucial
to the modeling of software. To obtain the state
change of the system, complicated law of motion
should be described in terms of mathematical model
or physical model. Then relevant calculated should
be made by setting values and boundary conditions.
Ordinary computer simulation system
implementation includes system modeling,
programming of the software, operation of the
software, analysis of experimental results and the
adjustment and improvement of the model. While
the mathematical modeling of simulation system for
physical education is actually carried out using the
personification compositing software package
VHSDK5.0 made by Chinese Academy of Sciences
(Fu Qiang, 2013). The example of each motion is
displayed by three-dimensional method and adjusted
and designed by means of visual interaction design.
After that the model will be verified using Euler’s
Theorem of Newton, obtaining standardized system
design. In terms of the movement of human body,
adjustments for the gestures could be achieved by
selecting and dragging rigid body from XY window.
By means of dragging, the variation quantity in X
Axis and Y Axis could be checked. By using Euler’s
Theorem, the rotation angle of euler angles 〈α , β ,
γ〉in the directions of zyx could be obtained. Then
the following relationship is obtained: