Distance dependent selective activation of three-dimensional objects in three-dimensional workspace interactive displays

A system, method and computer program are provided for a virtual three-dimensional workspace wherein dependent upon the position of the viewpoint with respect to a particular object, that object may be a functional interactive object with the user at the viewpoint if the virtual distance of the viewpoint to the object is within a certain specified distance. However, if the viewpoint moves beyond this distance, then the object is rendered noninteractive and becomes part of an aggregate object at the next distance level. In forming this aggregate object, the selected object joins a plurality of other noninteractive objects.

TECHNICAL FIELD 
The present invention relates to user interactive computer supported 
display technology and particularly to such user interactive systems and 
methods which are user friendly, i.e. provide even non-computer-literate 
users with an interface environment which is easy to use and intuitive. 
BACKGROUND OF THE INVENTION AND PRIOR ART 
The 1990's decade has been marked by a societal technological revolution 
driven by the convergence of the data processing industry with the 
consumer electronics industry. This advance has been even further 
accelerated by the extensive consumer and business involvement in the 
internet over the past two years. As a result of these changes, it seems 
as if virtually all aspects of human endeavor in the industrialized world 
requires human-computer interfaces. As a result of these profound changes, 
there is a need to make computer directed activities accessible to a 
substantial portion of the world's population which, up to a year or two 
ago, was computer-illiterate, or at best computer indifferent. In order 
for the vast computer supported market places to continue and be 
commercially productive, it will be necessary for a large segment of 
computer indifferent consumers to be involved in computer interfaces. 
Thus, the challenge of our technology is to create interfaces to computers 
which are as close to the real world as possible. 
Industry has been working towards this challenge and there is presently a 
relatively high degree of realism possible in interfaces. This presents a 
need and an opportunity for even more realistic interaction techniques to 
better match the visual metaphors used and to achieve a higher level of 
ease of use for computer systems. We are striving towards the 
representation of object as photo realistic, three-dimensional (3D) models 
rather than as the icons and two-dimensional desktops of conventional 
computer technology. 
Some examples of current technology for the creation of virtual 
three-dimensional workspace display interfaces are copending application 
Ser. No. 08/813,891 (Attorney Docket No. AT9-96-310), entitled "VIEWER 
INTERACTIVE OBJECT IN VIRTUAL THREE-DIMENSIONAL WORKSE", filed Mar. 7, 
1997, and Ser. No. 08/813,848 (Attorney Docket No. AT9-96-311), entitled 
"VIEWER INTERACTIVE OBJECT WITH MULTIPLE SELECTABLE FACE VIEWS IN VIRTUAL 
THREE-DIMENSIONAL WORKSE", assigned to the Assignee of the present 
application. 
A 3D virtual workspace display environment is also described in an article 
entitled, "RAPID CONTROLLED MOVEMENT THROUGH A VIRTUAL 3D WORKSE", Jock 
Mackinlay et al., Computer Graphics Publication, Vol. 24, No. 4, August 
1990, pp. 171-175, as well as in its related U.S. Pat. No. 5,276,785. 
It is clear that current technology in virtual three-dimensional workspaces 
has provided environments which are user friendly, i.e. make the casual 
computer user feel more comfortable and at home with the interface. 
However, researchers in human factors have found downsides to 
three-dimensional virtual reality displays. Because of the many choices 
that the user has in wandering down various "streets and roads" or 
visiting a wide variety of "buildings or stores" or going through many 
possible "doors", the user may wander through this reality and perhaps get 
lost from the track or goal he is pursuing. 
The present invention addresses this problem, i.e. that of helping the 
interactive user in three-dimensional graphic environments to stay focused 
and relate to the objects he is seeking to relate to in the manner he is 
seeking to relate to such objects even when these objects are arranged in 
3D space in what appears to be infinite configurations. The invention 
facilitates the user's navigation in the 3D space so that the user may 
easily keep track of his planned routes through this three-dimensional 
workspace, particularly when the user is narrowing in on a particular 
object for functional interaction. In the three-dimensional workspace, 
there are virtually hundreds of objects with which the viewer may 
potentially interact. Since the workspace resembles the real world, a user 
cannot interact with every object at every level of navigation. Many of 
the objects are just too "far away" in virtual distances for the viewer to 
practically interact with the object. The present invention is directed to 
a system for helping the user to narrow in on the object he wishes to 
interact with through a hierarchy of navigation levels through which the 
interactivity of objects is continually changing. 
SUMMARY OF THE INVENTION 
A key aspect of the present invention involves providing the user with a 
hierarchy of viewpoints and determining at each viewpoint level, which 
objects the user may functionally interact with. Thus, in a data processor 
controlled display system involving a three-dimensional display workspace 
having virtual user interactive objects in the workspace, viewer 
interactive navigation means are provided so that the viewer may navigate 
through a plurality of viewpoints into the three-dimensional workspace. In 
its broadest aspects, the present invention involves providing to a user 
an initial viewpoint at a first virtual distance from a selected object 
which is such a distance that a user can functionally interact with the 
selected object. Then means are provided for moving away from the selected 
object to a second viewpoint which is at a second virtual distance from 
the selected object at which second distance the user can no longer 
interact with the selected object. However, once the viewpoint reaches or 
exceeds this second virtual distance from the object, the object itself in 
combination with other inactive objects becomes part of an aggregate 
object which the viewer may interact with. 
Before proceeding further and elaborating the present invention, it should 
be understood that in order to navigate through three-dimensional space, 
view the space or relate to objects within the space, a viewpoint is 
determined within that space. That viewpoint is the virtual position of 
the viewer or person who is navigating within the three-dimensional space. 
The viewpoint is commonly defined by its position and its orientation or 
direction. For purposes of describing this invention, we will use the 
metaphor of a camera to understand the viewpoint. The camera's position 
and orientation are where it is and which way it is pointing. Let us refer 
to another property of a viewpoint which is "field of view"; this is 
effectively the resulting view from a given viewpoint. 
The present invention also involves the reverse of the process described 
hereinabove, i.e. it provides means for returning the viewpoint so that 
the viewpoint is closer than that second virtual distance from the 
selected object at which point there are means responsive to the return 
within the second virtual distance for rendering a selective object user 
interactive again and accordingly rendering said aggregate object 
noninteractive.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Before going into the details of specific embodiments, it will be helpful 
to understand from a more general perspective the various elements and 
method which may be used to implement the present invention. The present 
invention is implemented in three-dimensional virtual workspace. A 
three-dimensional workspace is a workspace that is perceived as extending 
in three orthogonal directions. Typically a display has a two-dimensional 
display surface and the perception of a third dimension is effected by 
visual clues such as perspective lines extending toward a vanishing point. 
Distant objects are obscured by nearer objects. The three-dimensional 
effect is also provided by showing changes in objects as they move toward 
or away from the viewer. Perspective shading of objects and a variety of 
shadowing of objects at different distances from the viewer also 
contribute to the three-dimensional effect. 
A three-dimensional workspace is typically perceived as being viewed from a 
position within the workspace. This position is a viewpoint. This 
viewpoint provides the virtual interface between the display user and the 
display. The viewpoint's direction of orientation is the direction from 
the viewpoint into the field of view along the axis at the center of the 
field of view. 
In order to present a three-dimensional workspace, a system may store data 
indicating "coordinates" of the position of an object, a viewpoint or 
other display feature in the workspace. Data indicating coordinates of a 
display feature can then be used in presenting the display feature so that 
it is perceptible as positioned at the indicated coordinates. The 
"distance" between two display features is the perceptible distance 
between them, and can be determined from their coordinates if they are 
presented so that they appear to be positioned at their coordinates. 
Techniques for providing and handling three-dimensional objects in a 
three-dimensional virtual workspace have been developed in the art and are 
available to display user interface designers. U.S. Pat. No. 5,276,785 
(Mackinlay et al., Jan. 4, 1994) is an example of the design techniques 
available to such three-dimensional workspace interface designers. 
The three-dimensional workspace or landscape is navigable using 
conventional three-dimensional navigation techniques. A user may move 
around or navigate within the three-dimensional data representation to 
alter his perspective and view of the displayed representation of the 
data. Thus, a user may be referred to as a navigator. The navigator is 
actually stationary, and his view of the display space changes to give him 
the sensation of moving within the three-dimensional graphical space. 
Thus, we speak in terms of the navigator's perceived motion when we refer 
to changes in his view of the display space. As the user moves, his view 
of the data changes accordingly within the three-dimensional data 
representation. 
The three-dimensional objects which will be subsequently described in 
embodiments of the present invention may be implemented using object 
oriented programming techniques, such as the object oriented techniques 
described in the above-mentioned copending application Ser. No. 08/753,076 
assigned to the Assignee of the present invention. The objects of that 
copending application are implemented using the C++ programming language. 
C++ is a compiled language. 
The programs are written in human readable script and this script is 
provided to another program called a compiler to generate a machine 
readable numeric code which can be loaded into, and directly executed by 
the computer. The C++ language possesses certain characteristics which 
allow a software developer to easily use programs written by others while 
still providing a great deal of control over the reuse of programs to 
prevent their destruction or improper use. The C++ language is well known 
and many articles and text are available which describe the language in 
detail. 
While the embodiment of the present invention, which will be subsequently 
described, can be implemented using object oriented techniques involving 
the C++ programming language, we found it preferable to use SCL as used in 
VRT: the Virtual Reality Toolkit developed and marketed by Superscape Ltd. 
having U.S. offices in Palo Alto, Calif. Extensive details of these 
programming techniques may be found in the Superscape VRT, Reference 
Manual, Version 4-00, 2d Edition, Jan. 29, 1996. 
It should be understood by those skilled in the art that object oriented 
programming techniques involve the definition, creation, use and 
instruction of "objects". These objects are software entities comprising 
data elements and routines, or methods, which manipulate the data 
elements. The data and related methods are treated by the software as an 
entity and can be created, used and deleted as such. The data and 
functions enable objects to model their real world equivalent entity in 
terms of its attributes, which can be presented by the data elements, and 
its behavior which can be represented by its methods. 
Objects are defined by creating "classes" which are not objects themselves, 
but which act as templates which instruct a compiler how to construct the 
actual object. For example, a class may specify the number and type of 
data variables and the steps involved in the functions which manipulate 
the data. An object is actually created in the program by means of a 
special function called a constructor which uses the corresponding class 
definition and additional information, such as arguments provided during 
object creation, to construct the object. Objects are destroyed by a 
special function called a destructor. 
Many benefits arise out of three basic properties of object oriented 
programming techniques, encapsulation, polymorphism and inheritance. 
Objects can be designed to hide, or encapsulate, all or a portion of, the 
internal data structure and the internal functions. More particularly, 
during program design, a program developer can define objects in which all 
or some of the data variables and all or some of the related method are 
considered "private" or for use only by the object itself. Other data or 
methods can be declared "public" or available for use by other software 
programs. Access to the private variables and methods by other programs 
can be controlled by defining public methods which access the object's 
private data. The public methods form an interface between the private 
data and external programs. An attempt to write program code which 
directly accesses the private variables causes a compiler to generate an 
error during program compilation. This error stops the compilation process 
and presents the program from being run. 
Polymorphism allows objects and functions which have the same overall 
format, but which work with different data, to function differently to 
produce consistent results. For example, an addition method may be defined 
as variable A+variable B, (A+B). The same format can be used whether the A 
and B are numbers, characters or dollars and cents. However, the actual 
program code which performs the addition may differ widely depending on 
the type of variables which comprise A and B. Thus, each type of variable 
(numbers, characters and dollars). After the methods have been defined, a 
program can later refer to the addition method by its common format (A+B) 
and, during compilation, the compiler will determine which of the three 
methods to be used by examining the variable types. The compiler will then 
substitute the proper function code. 
A third property of object oriented programming is inheritance which allows 
program developers to reuse pre-existing programs. Inheritance allows a 
software developer to define classes and the objects which are later 
created from them as related through a class hierarchy. Specifically, 
classes may be designated as subclasses of other base classes. A subclass 
"inherits" and has access to all of the public functions of its base 
classes as though these functions appeared in the subclass. Alternatively, 
a subclass can override some or all of its inherited functions or may 
modify some or all of its inherited functions by defining a new function 
with the same form. 
The creation of a new subclass borrowing the functionality of another class 
allows software developers to easily customize existing code to meet their 
particular needs. 
Although object oriented programming offers significant improvements over 
other programming concepts, program development still requires significant 
outlays of time and effort, especially if no pre-existing software 
programs are available for modification. Consequently, a set of 
predefined, interconnected classes are sometimes provided to create a set 
of objects and additional miscellaneous routines which are all directed to 
performing commonly encountered tasks in a particular environment. Such 
predefined classes and libraries are typically called "frameworks" and 
essentially provide a prefabricated structure as a basis for creating a 
working application program. 
In object oriented programming such as the previously described VRT 
software platform, there is provided for the user interface a framework 
containing a set of predefined interface objects. The framework contains 
predefined classes which can be used as base classes and a developer may 
accept and incorporate some of the objects into these base classes, or he 
may modify or override objects or combinations of objects in these base 
classes to extend the framework and create customized solutions in 
particular areas of expertise. 
This object oriented approach provides a major advantage over traditional 
programming since the programmer is not changing the original program, but 
rather extending the capabilities of the original program. 
The above-described Superscape Virtual Reality Toolkit (VRT) provides the 
architectural guidance and modeling, but at the same time frees developers 
to supply specific actions unique to the particular problem domain which 
the developer is addressing. Those skilled in the art will understand how 
the present invention is implemented using object oriented programming 
techniques as described above. 
With this background of the various expedients which may be used to 
implement the present invention, the preferred embodiments will now be 
described. 
Referring to FIG. 1, a typical data processing system is shown which may be 
used in conjunction with object oriented software in implementing the 
present invention. A central processing unit (CPU), such as one of the 
PowerPC microprocessors available from International Business Machines 
Corporation (PowerPC is a trademark of International Business Machines 
Corporation) is provided and interconnected to various other components by 
system bus 12. An operating system 41 runs on CPU 10 and provides control 
and is used to coordinate the function of the various components of FIG. 
1. Operating system 41 may be one of the commercially available operating 
systems such as DOS, or the OS/2 operating system available from 
International Business Machines Corporation (OS/2 is a trademark of 
International Business Machines Corporation). A program application such 
as the program in the above-mentioned VRT platform 40 runs in conjunction 
with operating system 41 and provides output calls to the operating system 
41 which implements the various functions to be performed by the 
application 40. 
A read only memory (ROM) 16 is connected to CPU 10, via bus 12 and includes 
the basic input/output system (BIOS) that controls the basic computer 
functions. Random access memory (RAM) 14, I/O adapter 18 and 
communications adapter 34 are also interconnected to system bus 12. It 
should be noted that software components including the operating system 41 
and application 40 are loaded into RAM 14 which is the computer system's 
main memory. I/O adapter 18 may be a small computer system interface 
(SCSI) adapter that communicates with the disk storage device 20, i.e. a 
hard drive. Communications adapter 34 interconnects bus 12 with an outside 
network enabling the data processing system to communicate with other such 
systems over a local area network (LAN), wide area network (WAN), or the 
like. I/O devices are also connected to system bus 12 via user interface 
adapter 22 and display adapter 36. Keyboard 24, trackball 32, mouse 26 and 
speaker 28 are all interconnected to bus 12 through user interface adapter 
22. Display adapter 36 includes a frame buffer 39 which is a storage 
device that holds a representation of each pixel on the display screen 38. 
Images may be stored in frame buffer 39 for display on monitor 38 through 
various components such as a digital to analog converter (not shown) and 
the like. By using the aforementioned I/O devices, a user is capable of 
inputting information to the system through the keyboard 24, trackball 32 
or mouse 26 and receiving output information from the system via speaker 
28 and display 38. 
There will now be described a simple illustration of the present invention. 
An embodiment will be described with respect to a virtual reality 
three-dimensional workspace of the type shown in FIG. 2. While the 
simplified examples of the present invention to be subsequently described 
with respect to the diagrams of FIGS. 3 through 6 and the process 
flowchart with respect to FIGS. 7A and 7B, do not specifically relate to 
the illustrative structures shown in the three-dimensional workspace of 
FIG. 2, the workspace of FIG. 2 will be first described in general to give 
the reader an understanding of the environment within which the present 
invention is operable. 
The three-dimensional workspace of FIG. 2 may be rendered by storing a 
virtual reality three-dimensional image creation program such as the 
previously described VRT of Superscape in the RAM 14 of the system of FIG. 
1. Also stored on the RAM will be a suitable operating system such as DOS 
or Windows. The operating system of the VRT application is 
diagrammatically shown in FIG. 1 as the operating system 41 in which the 
application 40 operates. 
The workspace shown in FIG. 2 is a portion of an even greater virtual 
reality workspace which will be understood to include various indoor and 
outdoor structures such as offices, living areas, entertaining areas, 
buildings, roads, etc. With all of these possibilities and possible paths, 
it may be readily seen how this virtual reality three-dimensional world is 
potentially quite complex and confusing to the viewer. The present 
invention is directed to making this world less confusing to the viewer by 
helping the viewer hone in on objects to which he wishes to functionally 
relate. The present invention accomplishes this through a hierarchy of 
areas and regions within the workspace. These areas or regions may be 
considered as aggregate objects containing a plurality of next lower level 
aggregate objects which in turn contain aggregate objects of the next 
lower level and so on until the selected functional object is reached as 
will hereinafter be described with respect to the diagrams of FIGS. 3 
through 6. 
In any event let us return to the image in FIG. 2, which for purposes of 
this illustration will be regarded as a high level viewpoint into a 
workspace divided into several general regions or areas: outdoor region 
42, side room regions 43 and 44, and main or central room region 45. Each 
of these regions in this viewpoint may be considered as an aggregate 
object at a high level which is an aggregate of a plurality of next lower 
level objects contained in each of the regions. For purposes of 
illustration let us concentrate on main room region 45. It is an aggregate 
of three objects: left table 46, right table 47 and entertainment center 
48. In turn, objects 46, 47 and 48 may be considered at the next lower 
level as aggregate objects. For example, table 46 is an aggregate object 
of object books 49 and 50. While entertainment center 48 may be considered 
as an aggregate object of TV 51, CD rack 52 and VCR 53. 
With this general background, we will now proceed to a description of an 
embodiment shown in FIGS. 3 through 6 which has been simplified to a plan 
or top view series of diagrams. The areas represented do not correspond to 
areas in the workspace of FIG. 2, but are a hypothetical workspace which 
has been simplified to bare outlines in order to more clearly explain the 
present invention. Let us assume that the initial viewpoint is viewpoint 
54. From viewpoint 54, the viewer sees at a high level or level 1, three 
major areas, 55, 56 and 57, which could be considered as rooms. These 
rooms are aggregate objects. For example, room 55 is an aggregate object 
containing objects: table 63, bookcase 64 and file cabinet set 55. 
Likewise, room 56 is an aggregate object of illustrative objects 58, 59 
and 60, while room 57 is an aggregate of objects 61 and 62 in that room. 
While this is diagrammatic, let us consider viewpoint 54 as presented to 
the user on a display interface such as that which could be shown on 
display monitor 38 of FIG. 1. In accordance with conventional techniques, 
the user may control the viewpoint through conventional I/O devices such 
as mouse 26 in FIG. 1, which operates through user interface 22 to call 
upon the VRT programs in RAM 14 cooperating with the operating system 41 
to create the images in frame buffer 39 of display adapter 36 to control 
the display on monitor 38. Viewpoint 54 may be changed using conventional 
virtual three-dimensional workspace navigation techniques. The viewpoint 
interface which is manifested as a three-dimensional virtual reality view 
into the workspace as shown in FIG. 2 is changeable as the user moves 
closer or backs away from objects in the workspace or moves to the right 
or left or up or down in the workspace. All this may be controlled by a 
suitable conventional I/O device such as mouse 26 of FIG. 1. While the 
movement in FIGS. 3 through 6, for simplicity of illustration, will be 
presented in a single plane, it should be understood that the movement may 
be along any lines in the three orthogonal, X, Y and Z directions. 
The invention will now be described in an embodiment relative to room 55 of 
FIG. 3. It should be understood that as long as viewpoint 54 remains at 
the position shown in FIG. 3, the viewer or user will be unable to 
functionally interact with any of objects 58 through 65. If there is to be 
any interaction, it can only be at the level of aggregate objects 55, 56 
and 57. However, let us assume that the user with conventional navigation 
techniques moves the viewpoint along path 67 until he enters room 55 at 
point 68. In doing so, he crosses line 69 which is the minimum distance 
("d") from objects 63, 64 and 65 at which room 55 can function as an 
aggregate object. Once line 69 is crossed, then the viewpoint is 
established, let us say, at point 68. Then, as shown in FIG. 4, objects 
63, 64 and 65 now considered aggregate objects at level 2, being 
respectively aggregate objects of the objects included therein, i.e. table 
63 is an aggregate of telephone 69, card file 70 and address book 71, 
while bookcase 64 is an aggregate of the books contained therein and file 
cabinet set 65 is an aggregate the file drawers in the cabinet. Thus, 
since objects 69, 70 and 71 on aggregate object table 63 are part of an 
aggregate, they still cannot be functionally interacted with from 
viewpoint 68. However, as shown in FIG. 4, when viewpoint 68 is navigated 
to viewpoint 73, the viewpoint is within the minimum distance d1 from 
table 63 necessary for table 63 to stop functioning as an aggregate object 
and objects 69 through 71 on table 63 are rendered functionally 
interactive and the system is at level 3 as shown in FIG. 5. At viewpoint 
73 in FIG. 5, the user may functionally interact with either telephone 
object 69, card file object 70 or address book object 71. The viewer 
selects address book 71 and proceeds to interact with the address book by 
turning pages and finding an address as shown in FIG. 6. 
With reference to FIGS. 7A and 7B, we will now describe the process 
involved in the present invention. FIG. 7A describes the steps relating to 
the creation of a virtual reality three-dimensional landscape, the 
creation of a hierarchy of three-dimensional objects within that landscape 
and the organization of the objects in that landscape into a hierarchy of 
aggregate objects. FIG. 7B describes how a particular navigation process 
with respect to functional objects is run using the programs of FIG. 7A. 
Thus, in FIG. 7A, first, step 75, the desired virtual reality 
three-dimensional workspace, such as the workspace shown in FIG. 2, is 
created. Then, step 76, there is created and stored a hierarchy of 
three-dimensional objects. Each object is interactive at a particular 
level of distance from the viewpoint and when objects are noninteractive 
because of distances from the viewpoint, they are organized to form into 
aggregate objects which are interactive at the particular distance. Also, 
step 77, there is accordingly stored in association with each object, an 
indication of the distance level at which the object is interactive, as 
well as the distance level at which the object is part of an aggregate 
object. Finally, step 78, conventional viewpoint navigation means is 
provided and stored. The process now proceeds to FIG. 7B where the created 
virtual reality programs are run, step 79. 
As previously mentioned, a program will be described in terms of the 
simplified diagrams in FIGS. 3 through 6. These will be assumed to take 
place in a virtual three-dimensional workspace such as that shown in FIG. 
2. The program initially sets up the workspace and object layout, step 80. 
Now in order to elaborate and perhaps better explain the flow of the 
present invention, we will assume that the viewer has navigated to a 
viewpoint where he is interactive with the selected object, step 81, FIG. 
7B. Let us assume that this is viewpoint 73 in FIG. 5 and the viewer is 
interacting with book 71 on desk 63. Then the user or viewer moves back 
from his selected object, step 82. Next, decision block 83 determines if 
the selected object is still interactive. Now, if in moving back from 
initial viewpoint 73 in FIG. 5 the viewer moves back to viewpoint 68 in 
FIG. 4, then, distance d1 will be exceeded and the objects on desk 63 
including interactive book 70 will be rendered inactive a and the decision 
from decision block 83 will be no. Accordingly, step 84, an aggregate 
object will be established including the selected object, i.e. aggregate 
object desk 63 including book object 71. Next, step 85, the viewpoint is 
moved back from aggregate object desk 63, e.g. to viewpoint 54 in FIG. 3, 
thus exceeding the distance d in FIG. 3 which renders desk 63 
noninteractive. Thus, the decision from decision block 86 will be no and, 
step 87, the next level aggregate object is established, i.e. room 55 
which includes desk 63. At this point, a decision is routinely made as to 
whether the session is over, step 88. If it is, the session is ended, step 
89. If it is not, then the system loops back to step 85 via point B. 
Likewise, if the decision from decision block 86 is yes, the system loops 
back to point B and step 85, the backup procedure, continues as previously 
described. 
Although certain preferred embodiments have been shown and described, it 
will be understood that many changes and modifications may be made therein 
without departing from the scope and intent of the appended claims.