Download Java 3D Car Shop (Report)

With these behaviors, the users can control the view navigate in the scene
freely. Another function the author intended to achieve was to attach a person
on the view, so when the camera position is changing the virtual person will
follow the camera position, it seems like the applet user is controlling the
person moving. In some aspects this is like a RPG (Role Play Game) game.
The way to attach a person on the view is to set an individual BranchGroup,
which is not belonging to the target TransformGroup. Therefore when the
camera position is changing, the view to the person will not be changed. This
is like the person always staying in the same position of the scene, so when
the scene graph is changed it looks like the user can control the person.
However there is a weakness to attach the person in this way. The navigation
function really is moving in the first person’s view. It is like your eyes moving in
the scene, but when a person is attached on the view, the user’s view is
changed to the third person’s view. The user is looking at the person moving.
This will cause the conflict of visual angle sometimes, especially when the
view is rotating or the view position is quite near to the objects. The scale of
the attached person related to the scene will become no sense at all. But in
some cases this would not cause serious problems. When the user is
navigating in the hall it looks acceptable.
The way to solve this problem is to allow users to detach the attached person.
This function is very necessary even through there is no visual angle
conflicting problem. Because when the applet’s users intend to check more
details of the products, the attached person will affect their view effect. So it is
good for users to remove the attached person in some cases. On the other
hand, with a person navigation in the scene can give users more realistic
feeling. The attached person can be a reference in some cases, for example,
when a user is checking a car; he possibly has no idea with the volume
concept of the car. It is very difficult for him to know the size of the car,
however if there is person in front of the car we can have an approximate
guess. Because we all know that a person is around 1.7 meter high. Having an
attached person in many cases can be very useful. So the attached person
should be allowed to add in the scene again after being removed.
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