Virtual Reality - Virtually Here
By
Linda and Erick Von Schweber
Introduction
"The Authors'
Cut": Excerpts from and additions
to the story originally published in PC Magazine Issue #5, March
14, 1995
Put
on your stereoscopic glasses and take a look around. Affordable
hardware and development kits are helping virtual reality get real
on the PC (or should we say unreal?).
The
world of computing is not flat but curved. Virtual reality takes
you into the third dimension, a place of many more possibilities
than you've seen through the flat glass of your monitor. You needn't
be bound to the two-dimensional realm of the graphical user interface.
The vehicles for exploration are available now, and they're as close
as your desktop.
Virtual
reality tools let you experience all kinds of "realities"
without ever leaving your office. Imagine taking flying lessons
without airsickness, or practicing surgery without stepping into
an operating room, or modeling data by grabbing it with your hand
and moving it around in a 3D space.
INTO
THE 3RD DIMENSION
What
is virtual reality (VR), and what is it not? After looking at and
working with an enormous range of products, some claiming to be
VR and some not, we've come up with a few definitions. Virtual reality
lets you navigate and view a world of three dimensions in real time,
with six degrees of freedom (6DOF): the freedom to move and look
forward and backward, left and right, or up and down.
In
essence, virtual reality is a clone of physical reality. In life,
you exist in three dimensions, you experience real time, and you
have the ability to interact with the world around you. VR products
mimic those conditions, even getting to the point where you can
"touch" objects in a virtual world and have them respond
or change according to your actions.
The
key here is interactivity, not gadgetry. Virtual reality is defined
by this minimum level of interactivity, and it isn't surprising
that interactivity is the key. A physicist will tell you that interaction
is the fundamental unit of physical reality.
How
you interact defines a VR experience, but how you interface with
it enhances that experience. In its most basic form, you interface
with a virtual world with your regular PC monitor; it serves as
a window into that world. You can enhance your experience with additional
technology that enables the virtual world to emerge from the screen
into the room. And with a head mounted display (HMD) or a CAVE (Cave
Automatic Virtual Environment) as your visual interface, your view
of the space around you is replaced by a virtual space which changes
as you move around. Looking up and seeing a virtual sky, or looking
down and seeing virtual ground, you're immersed in virtual reality.
If you use a CAVE, you can get a complete sense of immersion. You
use projection devices to create cave-like surroundings, incorporating
the walls and ceiling around you.
When
we observe a user immersed in VR, the specialized equipment dominates
our view. To the immersed user however, all this hardware becomes
invisible, playing a supporting role by enhancing the user's experience
of freedom in the virtual space. Freedom is what VR is all about.
STATING
THE OBVIOUS
Virtual
space can simulate a real space or an object. An architect can easily
allow a client to walk through the model of a proposed building
in real time. The difference between this scenario and a traditional
presentation shouldn't be taken lightly. In viewing blueprints,
still renditions, or even a pre-rendered animation that flies through
a model, the client's experience is totally passive. With VR, the
presentation is interactive: The client drives the show and is an
involved participant.
A
facilities planner and customer can configure a space together,
dragging and dropping machinery, office equipment, and movable wall
systems around. They can even experiment with colors, textures,
and lighting. This technique is applicable to retail and factory
planning and general product and package design. Movie and TV producers
can use VR for designing sets and storyboards.
With
more sophisticated VR software, you can model machinery, vehicles,
and devices, simulating the behavior of the actual equipment. This
saves dollars and development cycles before a product introduction
and provides training sessions with the virtual product when the
real product is scarce or prohibitively expensive. Many companies
are exploiting VR for these uses on the PC platform today.
Field
trips through VR are another great idea. Whether you want to explore
an ancient ruin, learn geography by walking the terrain, or tour
the space shuttle, VR is the next best thing to being there.
Virtual
space can also bring new worlds to life. For example, an industrial
chemist could use Autodesk's Cyberspace Developer Kit to test molecular
bonding sites for new drugs. Game makers regularly use VR to create
imaginary worlds for fictional adventures.
GETTING
INNOVATIVE
Things
get really interesting when you start to use VR dimensions to represent
non-spacial quantities and qualities. vrTrader, a VR application,
is one such package: It metaphorically turns financial data, stocks,
markets, and trading activity into objects in 3D space. vrTrader
is available from Avatar Partners Inc. (800-307-3254), and was built
using Sense8's WorldToolKit. The list price is normally $495, but
will be $395 for an unspecified length of time.
Spreadsheets
and graphs in the 2D world of DOS and Windows enabled millions of
users to "see" what had been invisible before. 3D visualization
of financial data in virtual space multiplies your ability to "see"
and interact with data as it changes moment by moment.
VR
is more than an enhancement for a few specific applications: It
can lead to a better way of computing. Operating systems and data
structures that are currently based on two-dimensional files and
folders, will soon be based on objects. You won't just pop open
folders; if you want to, you'll be able to walk through a virtual
office and open virtual filing cabinets. And this is just the beginning.
Programming languages have already blazed this trail. The interface
is sure to follow.
ENTERING
THE MULTIMEDIUM
An
equally exciting opportunity awaits the users and developers of
multimedia as VR takes them into the 3rd dimension. Hypertext becomes
an adventure of portaling between worlds, video emerges from its
box becoming integrated into a scene, and the talent-demanding tasks
of drawing, painting, and making clip-art look good is replaced
by bold, flying 3D text, quality 3D clip-models beautifully shaded
under dramatic lighting, and textures you can virtually feel. Whether
its a presentation for sales or marketing, a point of sale kiosk,
or a training application, VR takes multimedia into a new dimension
of user involvement and collaboration.
Suddenly,
surprisingly, virtual reality on the PC platform is no longer a
pipe dream. The chasm between multimillion dollar proprietary systems
and virtual reality products available for the PC is closing fast.
While there isn't yet a wealth of PC-based applications available,
the toolkits to build them and the hardware to experience them are
here now.
Copyright
© 1995 Ziff-Davis Publishing Company
|
Virtual Reality
- Virtually Here
By
Linda and Erick Von Schweber
Discovering
Virtual Reality
"The Authors' Cut":
Excerpts from and additions to the story originally published
in PC Magazine Issue #5, March 14, 1995
(Note
that due to space limitations this section was not published with
the story.)
Wow!
The logo has flown off the screen, floating so close you reach out
and touch it. Now you're flying - around a building - the VaporWear
fragrance factory, and there's the main entrance.
The
presenter hands you a mouse of some sort, and asks if you'd like
to see first hand how her company can handle your order? You take
the mouse, navigate through the door and look around the lobby.
Through
another door and you're maneuvering through the factory. By moving
your hand left you turn left, up and you move forward, down backward.
Signs direct you to the fulfillment department. Moving to a computer
display you actually enter a custom order. They're tracking all
the right information. Very smart.
In
manufacturing, you operate the simulated equipment, eagerly pushing
buttons and pulling levers. Clearly, they can produce your fragrence
easily.
In
the research lab you watch them test a new glass bottle. When it
drops to the floor and explodes, particles fly everywhere.
On
to packaging you examine the bottles and boxes from all angles,
inside and out. You choose a bottle style, stretch it tall, make
the glass purple and add your logo to the label. This could be a
great connection. They've got what you need. You can see that doing
business with them would be great. You're sold. Now where to for
lunch?
But
then you really start to wonder: was that a trip into Virtual Reality?
You didn't put on any goggles or gloves, but it sure feels like
you visited VaporWear. How did they do it? It was great fun and
informative. If it wasn't VR, what was it? What else is it good
for? How could you use it in your business?
Copyright
© 1995 Infomaniacs
|
|
Virtual Reality
- Virtually Here
By
Linda and Erick Von Schweber
Virtual
VR and Super VR
"The Authors' Cut":
Excerpts from and additions to the story originally published
in PC Magazine Issue #5, March 14, 1995
(Note
that due to space limitations this section was not published with
the story.)
Several
technologies we examined either fell somewhere short of our criterion
for VR or vastly exceeded it. We cover them here as they complete
the spectrum, the bigger picture in which VR fits. Virtual VR, the
low end of the spectrum, can be a useful introduction to VR for
some. Super VR is where PC-based VR is headed.
Animation
programs can produce Virtual VR - via pre-rendered movement through
a virtual world. Traditional 3D animation programs such as 3D Studio
generate .flc, .fli, and .avi files that can be used to create pre-rendered
fly-throughs but lack any freedom of movement in real time. Of particular
note here is Virtual Reality Labs' Vista Pro, an inexpensive, easy
to use program in which you can design terrains with trees, foliage,
water and more, then render a fly-through. Later this year HSC Software's
Bryce will come to Windows with animation capabilities, allowing
you to easily create worlds of incredible beauty on the PC and save
them as fly-throughs. Such programs currently provide levels of
detail and complexity beyond what can be rendered in real time in
VR today - but not for long!
Moving
up a notch we find Apple's QuickTime VR and Warp's VTV (Virtual
TV). Consider an image wrapped on the inner surface of a cylinder
or sphere. Now imagine looking through a camera while standing at
the center of the cylinder or sphere. Though you see only a small
portion of the scene at a time you are free to look up, down, and
around. You can even zoom your camera in and out. But you can't
move around. Warp promises this same viewing technique for video,
using a sphere - as the video proceeds you get to look around and
zoom in and out, similar in effect to viewing an Omnimax film projected
onto a huge dome.
VirtualVR
also includes immersive but passive forms of entertainment. These
include Disney's Star Tours ride as well as Universal Studio's Back
to the Future ride, both of which place you in a physical vehicle
on a motion platform, a trick learned from military flight simulators,
arguably the birthplace of virtual reality.
Today's
simulators, used by both the military and commercial aviation for
training provide the most compelling illusion of reality, commonly
raising their user's blood pressure and pulse. These devices, though
able to induce a sweat, are not the ultimate in VR. To provide the
absolute real time performance their simulated missions require
they must flatten or pre-compile the visual database, placing serious
constraints on what can and cannot be altered during a simulation.
You can't just land anywhere, get out, and walk around - all you
can do is fly.
Not
so constrained is the CAVE, or Cave Automatic Virtual Environment,
a technology developed at the University of Illinois in Chicago.
Several CAVE dwellers, donning Stereographic's CrystalEyes, may
enter at once, surrounded on 3 sides and below with a virtual world
that extends to within inches of your face and responds in real
time - thanks to the processing power of Silicon Graphics Onyx computers
with Reality Engine graphics acceleration. The CAVE is the closest
we have seen to Star Trek's Holodeck on the Enterprise. The downside?
For now a CAVE costs about $1 million and $30 thousand just to transport
and set up. But reality is getting cheaper. The new Sapphire pci
accelerator from Future Vision Technology can be installed 2 or
3 to a system. So equipped, a multiprocessor PC can drive the 3
stereo-ready projectors that create the CAVE experience.
Copyright
© 1995 Infomaniacs
|
Virtual Reality
- Virtually Here
By
Linda and Erick Von Schweber
The
Dimensions of VR
"The
Authors' Cut": Excerpts from and additions to the story originally
published in PC Magazine Issue #5, March 14, 1995
Styles
of Interactivity
Fly-Through
VR
Freedom
to move, turn, and look in any direction in the virtual space. This
is called 6 degrees of freedom (6 DOF). This is the defining characteristic
of a VR system. Example: a walk-through of a CAD model. A system
that provides less freedom of interaction may be useful but its
not VR.
Reactive
VR
All
the freedom of Fly-Through plus, when you interact with objects
they will either respond with a predefined behavior or allow you
to change them. Example: you can grab an object and send it flying
or you can pull on an object and change its shape.
Levels
of Immersivity
Through
the Window
A
standard computer monitor or data projector provides a "window"
onto your virtual world which appears to lie on the other side of
the screen. This is the experience of desktop flight simulator games.
In fact, this term originated with the first military flight simulators.
Into
the Room
A
stereo-ready monitor or projector displays a stereoscopic image,
you wear what look like sun glasses. The virtual world becomes quite
dimensional, appears to recede into the monitor and reaches out
towards you, into your room. For a sample experience don't miss
the next 3D movie that uses fancy polarized (not red/blue) sun glasses.
Immersive
When
you put on a head mounted display (HMD) you are transported into
the virtual world (visually at least). With head tracking the computer
knows and adjusts for where you are looking. Look up and see the
virtual sky, look down and see the virtual ground.
For
a sample experience play Virtuality's Dactyl Nightmare VR game.
The CAVE is also supremely immersive.
Copyright
© 1995 Ziff-Davis Publishing Company
|
| |
|
Virtual Reality
- Virtually Here
By
Linda and Erick Von Schweber
Virtual
Reality Software
"The
Authors' Cut": Excerpts
from and additions to the story originally published in PC Magazine
Issue #5, March 14, 1995
To
develop a VR application, you need the best tools for the program
you want to build. Here we take a look at development products that
provide 6DOF navigation with real-time rendering within a world.
Unless otherwise noted, all testing was conducted on a 90-MHz Pentium-based
Hewlett-Packard Vectra XU5/90C with 32MB RAM and a Matrox MGA Impression
Plus PCI graphics accelerator.
If
you want a basic VR package, either for a fly-through application
or just for getting your feet wet in VR, then these products are
for you. Using Virtus WalkThrough Pro's Windows-based graphical
interface, you can point and click your way to a world of your own.
Mind you, there are limits: There is no facility to import objects,
and there is no sound. The textures are only 256 colors, you can't
communicate with other Windows applications, and objects can't respond
to your input. The current Windows version won't let you import
Video for Windows or QuickTime movies as surface textures.
If
your needs are limited to creating and exploring a model of a house,
building, or manufacturing or distribution facility, this product
is a good match. The Windows point-and-click development environment
lets you keep one window open with a design view window (with a
view from the front, top, side, or bottom) along with another window
in which you can fly through the 3D, rendered view (the walk window)
of the world you are building. Toolbar icons are used for most everything.
You pick a shape, position and size it in the design view window,
and use an icon to connect it to another shape if you want a doorway
between them. You can use another icon to draw doors and windows
onto walls. The interface is not totally intuitive but it does present
an accessible approach to 3D design. Creating furniture or other
objects is tedious at best, but Virtus ships outstanding object
libraries.
There
is everything you need for offices, homes, kitchens, bathrooms,
and the like. We created a building of four connected hexagram rooms
in a few minutes, and we loaded furniture for offices, sitting areas,
and a bathrooom. We were able to apply wallpaper, install carpet,
and change the colors and fabrics of furniture. Even creating doorways,
roofs, and stairways is a breeze. We could walk around the world
at any time during this construction process.
By
deploying Virtus WalkThrough Pro in this development mode rather
than in a runtime, you have partially reactive VR. You can work
with a client to reconfigure the world, walk around it, and change
it some more. The only problem here is cost--you need the full product.
You can freely distribute fly-through-only worlds using the Virtus
player on PCs, Macs, and PowerMacs. The Virtus player ships with
Pro but not with Virtus VR; you can get it free from the company
or download it from on-line services.
We
built most of a four room building with a 486/66 HP Vectra. Performance
was quite good until we crashed the system with an excess of textures.
The same file ran fine on the Pentium. We tested the shipping version
of Virtus WalkThrough Pro 2.0 ($495). Virtus VR ($99) offers fewer
tools--and only drag-and-drop manipulation--to create and modify
worlds but can use all the galleries.
If
basic VR is what you're after, requiring only a standard computer
and desiring no special peripherals (Virtus only supports a mouse),
the Virtus products should be on your shopping list.
If
you haven't seen VREAM's VRCreator in a while, take another look.
Sporting a new graphical interface (in Windows) and improved shading
and textures thanks to RenderMorphics rendering, VRCreator takes
the high functionality that's been a trademark of VREAM and makes
it very usable. We looked at a pre-release version of VRCreator,
Version 2.0, and although it had only some of the finished product's
features, it impressed us.
Using
point and click, we created objects from a rich set of primatives,
extrusion, and lathing options. Then we easily sized and positioned
them, assigned textures, and modified lighting. You will also be
able to import .DXF files and .3DS files (possibly including animation
files). Most impressive is the Link feature, which is used to connect
objects, actions, and reactions. You open a Link dialog box, select
an object or objects to link, select a condition, choose the object
that will respond, select the response, and save the link. Simulating
devices was never this easy.
For
compatibility with past versions, VREAM has retained its original
scripting language. Though a boon to early adopters of VREAM's former
DOS product, this language lacks the object orientation its new
interface implies.
How
well does this new version exploit the strengths of Windows? It
will support DDE, MCI, OLE; .WAV and MIDI files; and possibly Video
for Windows. Should the company achieve all this in a $495 product,
it will have brought multimedia into the third dimension. If you
want VR power without the hassle of a toolkit, VRCreator is the
product to get.
Sense8's
WorldToolKit lets you do anything in VR. WorldToolKit development
tools run on many platforms, from DOS and Windows in all its variants
to Unix on Sun, HP, IBM, DEC, and SGI.
Sense8
supports nearly every VR interface device, including headmounts,
trackers, 6DOF input devices, 3D sound controllers, and the all-important
graphics accelerators. Documentation is extensive and the company
routinely configures systems and offers full consulting and contract
development. Sadly, WorldToolKit's interface and architecture are
starting to show signs of age.
WorldToolKit
consists of a library of C functions. You build your virtual world
by writing code to call WorldToolKit functions. The development
environment differs according to platform; for instance, in Windows
NT you do development from within Visual C++. These function calls
are used to initialize a world; import, size, or move an object;
define behavior; add sensors to accept user input and detect user
motion; and locate the user's viewpoint. This is all done in code.
You then compile and link. Sense8 is to be commended on the fact
that its function library is object-oriented. It does not, however,
deliver all the productivity advantages of true object-oriented
programming.
We
examined WorldToolKit running on DOS, Windows 3.1, Windows NT 3.5,
and two demos produced with an pre-release version of WorldToolKit,
Version 2.1 for Windows NT accelerated by a pre-release Evans and
Sutherland Freedom Graphics PCI board. One of the accelerated demos
featured a completely textured environment with many objects moving
and flying through the environment. We were able to move through
the space at anywhere from 8 to 13 frames per second. This is impressive,
as we have seen other vendors' systems crash just loading highly
textured worlds.
Sense8's
documentation deserves a special mention. Tips and tricks are found
throughout the user and reference manuals, and a hardware section
familiarizes the reader with the full range of supported devices.
Numerous demo apps are shipped with the product with complete source
code. Studying these programs will tell you how to link your virtual
world to spreadsheet data in real time, provide the basics of implementing
collision detection (to prevent the user from navigating through
a wall), tell you how to animate objects in your world, and provide
links between multiple worlds so the user can portal between them.
Sense8
has another product coming: an object-oriented graphical IDE program
for power users. It will use Visual Basic as a scripting language
so that, even while immersed, you can define or change an object's
behavior dynamically by dragging Visual Basic code onto it.
If
being prepared for all the possibilities is important for your application
and organization, and programming talent is available, WorldToolKit
is the world builder for you.
Open
Inventor, the newest kid on the PC block, is licensed by Silicon
Graphics Inc. (SGI) to a number of companies who are supporting
it across several platforms. One licensee, NeTpower, released Open
Inventor for Windows NT in the fall of 1994, and new ports should
be shipping as you read this from Template Graphics Systems (TGS)
and Portable Graphics. In 1995, ports of Open Inventor will span
all desktop operating systems.
Open
Inventor is an attempt to redefine the realm of interactive 3D graphics.
While Open Inventor is a C++ toolkit which is used from within Microsoft's
Visual C++ in Windows NT, it adds its own interface wizard to Visual
C++. The wizard adds menu items and icons to your programs, extending
their functionality. It also provides object manipulators, which
add wireframes around any object (in the runtime environment) and
let the end-user reshape, resize, and reposition any object in the
world.
At
Open Inventor's heart is an object-oriented database called a scene
graph, an elegant structure that stores the information for creating
an animated, interactive 3D world. Such information includes objects
and their attributes, lighting, cameras, engines that provide motion
and calculation, manipulators, events, shapes, and actions. Related
to this database is a new file format, with the extension .IV, called
the Open Inventor Interchange Format. It lets you send interactive
3D worlds across a LAN or around the Internet and run on dissimilar
computers.
The
NeTpower port of Open Inventor is flexible enough to support simulation,
visualization, and VR. Once you understand the structure of the
scene graph database, creating an application is as simple as writing
a C++ program to populate the scene graph. You execute your program,
it loads the database into memory, and your world is operational.
No other program we looked at could even begin to approach the great
design of this model. Inventor also provides an OpenGL rendering
solution, as do workstation level modeling and animation programs,
to produce remarkably great-looking graphics. Besides running this
on our test bed we tried it out on an Intergraph TD-4, where it
performed very well.
Although
the NeTpower port ran without a hitch, it lacks a visual scene editor,
a graphical window in which you interactively build your scene graph
before refining it with C++. The Template Graphics port is expected
to include this feature and a file format conversion utility, also
lacking in the NeTpower port, to import and export non-.IV files.
The
documentation shipped by NeTpower is almost non-existent. Programmers
must instead rely on two texts on Open Inventor written by Josie
Wernecke, a member of the SGI development team. The SGI books (available
at computer bookstores) are great as tutorials but not as reference
manuals. Also, the NetPower NT port has Windows-specific features
that SGI books don't address.
The
product has some limitations. Global behaviors are not in the Inventor
model: You must either make them local to objects or look to another
product. We are also not convinced that enough support exists for
morphing of objects.
What's
clear, though, is that because it is a highly portable and flexible
standard, Open Inventor is soon to be the talk of the VR town.
(We believe Inventor scene graphs and the .IV file format will become
the graphics world's equivalent of SQL relational databases. Consider
how RDBMS have revolutionized information processing and you begin
to see the impact this new standard will have. Open Inventor is
very much a "live" project at SGI. We spoke with Rikk
Carey, the father of Inventor, who told us how his progeny is now
entering its 2nd phase of development. The goal: to take 3D from
a niche tool to a ubiquitous technology. No 3D desktops for him.
He sees nothing short of a visual workplace spanning the office,
the university, and with the internet the entire global community.
This is Open Inventor's mission.
How's it doing so far? As of Fall '94 Open Inventor had two to three
thousand licensed developers and 10 thousand university licenses.
Ports of Open Inventor will, this year, span "all" of
Microsoft's Windows implementations, PowerMac OS, OS/2, IBM's RS/6000,
Sun, DEC Unix, HP Unix, and of course SGI Irix. And licensees will
benefit from SGI's continuing R&D on Open Inventor. No less,
And George Lucas's Industrial Light and Magic uses Open Inventor
as the hub of their 3D graphics and animation system. Pretty impressive
for a 5 year old. Open Inventor's heritage dates back to 1989, the
result of an R&D project at Silicon Graphics.)
Autodesk's
Cyberspace Developer Kit (CDK), Version 2.0, is a C++ toolkit providing
C++ classes that you can make instances of in your programs. You
develop in Windows NT and can execute in both NT and Windows 3.1
with the Win32s and WinG extensions. You work in Microsoft's Visual
C++, writing code; Autodesk has not added any wizards or other interface
tools.
CDK
can do some incredible things, but this power comes at a great cost.
Application development is challenging, so be prepared to write
a lot of code. Just setting up the environment to render a static
object requires pages of programming.
CDK
is distinguished by its support for physics. Whether you need mass,
gravity, springs, friction, or collisions, CDK provides a powerful
set of primitives. To simulate additional Newtonian physics, you
have workable support for matrix and vector algebra. The package
is very useful to the game developer who wants to create super-realistic
motions of solid bodies in space.
Also
of note is CDK's support for importing an animation produced in
3D Studio and running it in your virtual world as you navigate and
interact. This is a great feature, since producing complex animations
in a VR environment is typically not an easy task. In practice,
the animation tended to slow down during navigation through our
VR world, but generally we remained impressed.
Compared
with the other toolkits we examined, CDK offers limited cross-platform
support--basically Windows 3.1 and Windows NT. Nevertheless, if
you love to program, and you can exploit CDK's strengths in physics
and animation, as well as its flexible architecture, this may be
the VR toolkit for you.
The
demos that come with Superscape VRT comprise a virtual doctoral
program in VR interactivity. We explored Superscape VRT 3.6 for
DOS (look for a Windows version in August, 1995). It's a standalone
system, containing world and object creating and editing tools,
the company's procedural SCL language, a bitmap editor for textures,
a sound editor for .WAV files, and, most amazingly, a built-in key-frame
editor for producing animations and morphs. Also unique are the
ability to specify ground, sky, and horizon colors, and the inclusion
of a ground/floor that you never fall off and can edit easily.
The
interface suffers from the DOS-based GUI, however. Strange--it just
feels old even though you're creating VR. The graphics tools are
basic, the objects shipped are lacking in style, and you may have
trouble importing most .DXF files. Most troubling, however, is the
lighting methodology. You actually have to assign color variants
for an object when its colors are lit and for when its colors are
not lit. The result is a very flat, limited visual quality.
Superscape
does achieve impressive graphics performance on 486-based PCs if
you have a graphics card with excellent DOS performance. Interaction
is Superscape VRT's strong suit. Without programming, you can assign
behaviors such as actions, rotations, gravity, and elasticity to
objects. We built a room and placed a ball in it, and then it was
easy to set things up so when a user moved the ball it would begin
to rotate, bounce all around the room, and slowly lose its bounce.
You
can also use the keyframe editor to produce a bouncing ball, complete
with "squash" effects, and run the animation whenever
someone touches the ball. Add some conditional SCL programming,
and you have a very flexible set of options for building interactive
worlds.
If
you want a DOS product that doesn't require programming, Superscape
VRT is the only choice. The $3,995 product is robust and field-tested,
relatively easy to use, and backed by creative people experienced
in virtual world design and building.
Copyright
© 1995 Ziff-Davis Publishing Company
|
| |
|
Virtual Reality
- Virtually Here
By
Linda and Erick Von Schweber
Creating
Realities - A Guide to VR Development
"The
Authors' Cut": Excerpts from and additions to the story originally
published in PC Magazine Issue #5, March 14, 1995
(Note
that due to space limitations this section was not published with
the story. The story had an abbreviated list of tips.)
Design
methodologies tell us to choose development software according to
our needs, then select the hardware that best supports the chosen
software. This is fine for traditional applications where the "interface"
is constituted strictly of software and the hardware is a commodity.
With VR the interface is built of both software and varied hardware.
So, where to begin?
Start
with a description of the application you have in mind and its intended
users. Characterize its style(s) of interactivity and level(s) of
interface, allowing for future evolution. Compare that with the
hardware, software and sample configurations in this round up. And
keep your options and mind open. This arena is moving rapidly.
You
should now have a list of products and vendors to accompany your
description. Ask manufacturers of hardware to recommend compatible
software. Ask software vendors to recommend coordinated hardware.
We've found both types of vendors to be bountiful sources of information
and they are very willing to provide such. In fact, many of the
vendors covered in this story offer consulting, contract development,
systems integration, and turnkey systems in addition to product.
In all they're a highly knowledgeable lot.
Consider
the expertise each development environment requires.
Point
& Click
Purely mouse driven through point and click, these programs are
well suited for end-users.
GUI
and Scripts
These programs rely primarily on a GUI (DOS based or Windows) but
can be extended with an included scripting language. Appropriate
for the power user, an option for the programmer.
C++
Toolkits
To be used in even the most trivial fashion these toolkits require
skill in C++. However, by supporting Microsoft's Visual C++ for
Win NT code management, compiling and linking are greatly simplified.
Design
Carefully
We
recommend creating and importing the objects, defining their attributes,
and getting them positioned. Add animation, lights, and viewports
(aka cameras). After you are happy with the general lay out of the
world, develop any interactive behaviors. Special features, such
as DDE Links and OLE2.0 hooks to other programs can then be addressed.
Populate
your world
Creating
objects can be a difficult job. Some programs are self-contained
and include tools to create, color, and texture 3D objects. One
or two ship with large libraries of objects. None of them has strong
interactive modeling tools. If the program successfully imports
.dxf or .3ds files, you should create your objects in a modeling
or animation program. Usually, 3D text is easy.
Don't
forget to count your polygons
Macromedia's
Macromodel includes an optimizing function that reduces the polygon
count of existing 3D models, an important feature as smaller polygon
counts means better performance. An IPAS plug-in from Schriber does
the same for Autodesk's 3D Studio. TreeTool and TerrainTool from
InWorld are self-descriptive and produce low polygon .dxf files.
Vista Pro from Virtual Reality Labs provides unoptimized .dxf files
of actual landscapes from around the globe.
ClipModels
- unfinished furniture and buildings
You
won't always need to create your objects from scratch. A wide array
of 3D clip models is available from Accuris, Viewpoint, Syndesis,
Visual Software, and Noumenon Labs. Accuris and Syndesis also offer
format converters.
Objects
have properties, they respond and mutate
In
most of the programs you define the objects, determining if you
can pass through their walls, move them, rotate them, or simply
touch them. Objects that can be touched can usually have a response
declared, so they will move or start an animation sequence or rotate
or change colors or whatever. Some programs let interaction with
one object affect another object, pulling down the light switch
dims the lights, pushing a button on the radio plays a .wav sound
file.
Object
mutation is really fun if you are the adventurer to a virtual world,
where suddenly you can change the shape, color, texture of an object,
like magic.
Add
some animation and video
In
a few cases, you can even import animations in .3ds format. Most
will at least cycle through a series of bitmaps or objects to provide
the sense of animation. Only one program provides its own keyframe
editor and can morph objects interactively. In the windows programs,
.avi files can sometimes be played inside your world. It's starting
to look a lot like multimedia...
Sometimes
objects have physics
Minimally,
all these programs can give objects collision detection - they can
tell if you are running into something and keep you from flying
through the wall. Elasticity, weight, and gravity are common. Very
complex simulations can be created with acceleration, springs, oscillation,
...
Textures
provide depth
Texture
libraries are available but with Kai's Power Tools from HSC Software
and Adobe Photoshop you can create your own. They should be used
sparingly (they do slow performance down) to provide realism or
surrealism, from wood grains to shiny space bubbles.
Virtual
Horizons
HSC's
KPT Bryce (Available soon for PC's) produces stunning bitmaps of
natural landscape forms, great as backgrounds to add realism to
your virtual world. Vista Pro can work in this capacity too. Apply
to either the inside of a dome or cylinder, providing a realistic
horizon and a world you can't fall off of. For photorealism, try
Aris Entertainment's Media Clips.
Worlds
aren't Silent
Remember
that VR is not all visual, many development environments support
sound as well. Licensable collections of both MIDI and .WAV music
are available but too numerous to list. Sound effects libraries
such as [TKTK] are great for opening and closing doors and such.
Performance
tuning can be complex
Standard
techniques include making objects invisible if they are hidden,
dynamically deleting /replacing objects depending on their visibility.
Another technique is to reduce the detail rendered when the image
is very far away.
Visual
Quality is not a given
Image
quality runs the gamut, from 256 pallatized colors thru beautifully
rendered 24 bit (16.8 million colors) images. Amazingly - you might
not see the performance difference you'd expect. But 16 bits (65,000
colors) seems to be the favorite balance between aesthetics and
performance.
Lighting
implementations range from primitive to awesome. Never underestimate
the value of lights to your world.
Copyright
© 1995 Infomaniacs
|
|
