Object
Selection and Manipulation
·
There are a
number of well-known selection metaphors
o
Arm Extension.
This allows the user to extend their arm to reach a distant object in the
virtual space There are several subclasses of this metaphor.
o
Ray Casting. Here
a “light ray” extends from the user’s finger and selects the object it
intersects with.
o
Image-plane. This
metaphor “removes” depth from object selection. The user can select an object
by placing their hand between their eye and the object.
·
One feature of
object selection is that the user may want to manipulate the object that has
been selected.
·
Standard “Virtual
Hand” manipulation of object combines poorly with many selection metaphors.
·
[Bowman] found that one of the most usable
selection/manipulation combinations was a technique he developed called “HOMER”
(Hand-centred Object Manipulation Extending Ray-casting) which is a combination
of ray-casting and automatic transportation.
