Let's face it: navigating a 3D world using many of the current VRML
browsers is a difficult proposition at best. Users often wind up
upside-down, staring off into space, or miles from where they intended
to be. And frustrated users are unlikely to come back for repeat
Much of the difficulty can be addressed by
browser writers. As browser developers do user testing, learn from the gaming
and research communities, and iterate on designs, the browsers will get
more usable. But until then, there are plenty of things you, as a VRML
author, can do to help users have a good experience.
One, one thousand, two one thousand...
The first three things to think about when designing worlds for good
navigation are frame rate, frame rate, and frame rate. As the frame
rate drops below about 5-7 frames per second, navigation gets
increasingly difficult. If the user is moving at all quickly, there
will be large jumps in position between each frame. First you're here,
then *poing*, you're 30 meters ahead. This is disconcerting, to say the
least, and makes both quick movement and fine positioning very hard to
Test your worlds on the target platform, and make sure that they run
quickly enough. It is better to remove some polygons or textures than
to have a beautiful world that no one can see or move around in.
Embed your VRML world in an HTML page, as if it's a one-frame comic strip. Smaller
windows into the scene will generally render faster.
Help, I'm blind! (or Nobody told me this thing had feet.)
Try this: take a piece of posterboard and cut a six-inch by three-inch
rectangle out of the middle of it. Now, hold it up in front of you and
(ignoring all the funny looks you will get) try walking around, looking only
through the rectangular hole. You will probably trip over a few things
and bang your knuckles on a doorframe before you get very far. That's
the experience that we're all having in 3D worlds. Users can't see or
feel their outer perimiters, so when they hit their shins or shoulders on something, it's
difficult to understand what is happening.
Pay attention to the avatarSize field in the
NavigationInfo node. Set these values so that they make sense for your world.
Build wide doorways and short steps, so that the user can confidently
navigate without needing to look to the side or down.
Don't leave your skateboard in the driveway. Again, looking down while
navigating is tough. Don't build objects that are taller than the step
height that's in the avatarSize field, and yet are so short that the
user can't see them at the point of collision. (The default step height
The first step to a cure is recognizing the problem...
"Yesh, ossifer, I can walk a straight line if I could just get
this browser to do what I want..." In many browsers, it's rather
tough to make fine corrections. Getting from here to there often
involves a few swings back and forth as the user corrects, then
overcorrects, then corrects again, etc.
Don't build worlds with sharp corners. Turning corners is particularly
difficult, and often involves much banging into walls and cursing
before the user makes it. Gentle, sweeping curves work best.
Build wide doors. Once the user has collided with the edge of a door,
it can be very hard to get straightened out. Best to just make it wide
enough in the first place.
Where am I? Where was I?
We can learn from folks who have been studying the problem of people
navigating for a long time. It turns out that there are a few basic
ways that people divide up the world when they're thinking about
Paths - hallways and passages
Edges - walls and fences
Landmarks - things that stand out from their surroundings
Nodes - pieces of the world with similar characteristics
Districts - logically separate sections
Use landmarks. Putting a tall yellow neon obelisk in your main square
is a great way to ensure that users can find their way back there from
anywhere in the world. (Okay, so a neon obelisk would be ugly, but you
get the point.)
Create nodes. Use color, theme, or shape (or whatever) to group parts
of your world. "I remember I was in the blue section when I saw
the paisley whale."
Use audio. Sound can create a powerful sense of place, and the
spatialization can act as a direction finder. Environmental audio can
create both landmarks and districts.
You've gotten the user to click on your very snazzy world, they've
waited for the inlines to appear, they're all ready to have a great
experience, and ..... How does a user know what there is to do and to
Use viewpoints. Well-named viewpoints can tell users a great deal about
what they might find interesting. By just using page-up and page-down
(in most browsers), users can get a quick idea of where all the good
Use in-scene widgets combined with viewpoint animation to navigate for
the user, as Sam Chen did in OOBE using arrow images like small signposts. This
relieves the user from figuring out how to navigate and where to go. If
the main point isn't navigating, but instead what to do when you get
there, this method can be very effective.
How do I get off this crazy ride?
You click down, give the mouse a confident sweep.....and suddenly end
up feeling like a bird who smacked into a window. The world revolved
around you, and you're up-side down and backwards. What happened?? You
thought you were in "Walk" mode, but you were actually in
Use the type field of the
node. The truth is that Examine mode works great for single
objects floating in space, but is lousy if the world has a floor and a
ceiling. The new
changes to the spec mean that authors (yes, you) have much more
control over type. If you specify type as ["WALK",
"FLY"], then the user won't be able to get to the Examine
viewer in the first place.
 Lynch, K. (1960). The Image of the City.
Cambridge: MIT Press.
 Darken, R.P. and J.L Sibert, A Toolset for
Navigation in Virtual Environments, in UIST '93.
Atlanta, GA: ACM Press.