MATLAB SIMULINK 3D ANIMATION 5 Manuale Utente Scaricare il pdf (Pagina 33)

Note: Sometimes it is also necessary to correct bugs introduced in the file by

the CAD tool export filter. As VRML format is a text-based format codified by an

ISO standard, these bugs are relatively easy to identify and correct.

5.2.4. Creating a Virtual Scene

The VRML file, adjusted manually in the previous steps, is ready for association

with Simulink or SimMechanics models. However, in order to work with the

virtual scene effectively, it is suitable to make some additional modifications to

the scene file. These changes can be added on an ongoing basis, in parallel with

developing and using the dynamic model.

These modifications can be done using a text editor, V-Realm or any other

VRML editor:

 Adding the WorldInfo node with scene title (used as virtual world

description in Simulink 3D Animation)

 Adding the NavigationInfo node defining the scene default navigation

speed and avatar size that ensures correct displaying the object from

near and far distances.

 Adding the Background node to specify a colour backdrop that simulates

ground and sky, as well as optional background texture – panorama for

the scene.

 Adding several viewpoints to be able to observe the object conveniently

from different positions. The viewpoints can be static (defined as

independent objects at the top level of the scene hierarchy) or attached

to objects that will move in the scene to be able to observe them during

simulation. Such viewpoints are defined as siblings of moving objects in

the scene hierarchy. An example of a viewpoint moving with the object

can be the viewpoint Ride on the Plane in the Simulink 3D

Animation demo file vrtkoff.wrl.

 Adding lights to the scene in order to illuminate it. Although VRML

viewers have always a “Headlight” available, it is a good practise to

define lights in the scene so that it looks for every user in a consistent

way, according to the scene author preferences. Most useful type of

VRML light to illuminate a whole scene is the DirectionalLight node. It is

practical to use combination of several such lights to illuminate objects

from several sides.

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MATLAB SIMULINK 3D ANIMATION 5 Manuale Utente Pagina 33