User`s guide

1 Getting Started
1-14
The VRML coordinate system is different from the MATLAB and Aerospace Blockset™
coordinate systems. VRML uses the world coordinate system in which the y-axis points
upward and the z-axis places objects nearer or farther from the front of the screen. It
is important to realize this fact in situations involving the interaction of these different
coordinate systems. SimMechanics uses the same coordinate system as VRML.
Rotation angles — In VRML, rotation angles are defined using the right-hand rule.
Imagine your right hand holding an axis while your thumb points in the direction of the
axis toward its positive end. Your four remaining fingers point in a counterclockwise
direction. This counterclockwise direction is the positive rotation angle of an object
moving around that axis.
Child objects — In the hierarchical structure of a VRML file, the position and orientation
of child objects are specified relative to the parent object. The parent object has its local
coordinate space defined by its own position and orientation. Moving the parent object
also moves the child objects relative to the parent object.
Measurement units — All lengths and distances are measured in meters, and all angles
are measured in radians.
VRML File Format
You need not have any substantial knowledge of the VRML format to use the VRML
authoring tools to create virtual worlds. However, it is useful to have a basic knowledge
of VRML scene description. This helps you create virtual worlds more effectively, and