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15
HUDs in Virtual Environments
Never trust a computer you can’t throw out a window.
—Steve Wozniak
15.1 WHAT ARE HUDS?
Not surprisingly, HUDs or heads-up displays are made from the same stuff that makes up the rest of your
virtual world: prims and meshes, textures, and scripts. They are custom concoctions of shapes, colors, tex-
tures, and scripting that are created by content makers to help you access the functionality of their virtual
products or to provide game-playing devices like tools, weapons, or counters. Instead of wearing a HUD on
your avatar or walking your avatar into a HUD, you attach it to your screen. The HUD will occupy part of
your computer’s screen space in the position you choose until you decide to detach it. Let’s explore how a
HUD attaches itself to your screen by using a simple cube.
15.1.1 aTTaChing a CuBe prim To your sCreen To TesT hud alignmenT
Follow these steps, illustrated in Figure15.1, to see how a cube will align as a HUD to your screen:
1. Rez a cube on the ground and name it Test_HUD.
2. As you know, every cube has six faces. Change face 4 to a red color; keep the overall texture at
the default “plywood” setting for now. With the Firestorm Viewer, you can nd out what the face
number is by selecting a face and checking the Build/Texture menu. The face highlighted is shown
there just below the Link and Unlink buttons (see the highlighted box in Figure15.1).
3. Once you have colored face 4, take the cube into your inventory. To attach a HUD is easy; simply
nd the Test_HUD object in your inventory, right click to open the Actions menu, and select Attach
to HUD/Center. A red square should appear at the center of your screen; you are looking at face 4
of the cube, attached in the center position. This is shown in the lower image #3 of Figure 15.1.
4. To detach your Test_HUD cube from your screen, simply right click on it and pick detach from the
pie menu.
5. Try attaching the cube in the other HUD locations and see how it looks in each one. In some cases,
the Test_HUD may be mostly off the screen. This should indicate to you that the size of a HUD is
just as important as the spot it is located on the screen.
6. Detach the Test_HUD one more time and save it in a new folder you have named HUD_builder for
future use.
As you can see from your experimentation, there are eight possible starting positions for the attachment
of a HUD. Let’s consider the relative importance and “rank,” if you will, of each position on the screen.
Obviously, the center and center 2 on the drop down menu are the most dominant positions. Since they
occupy the middle of your eld of view, they would be used for HUDs that are of primary importance for a
short amount of time, such as reading a text, looking at a map, or perhaps choosing the settings on an avatar
296 Virtual World Design
1 & 2
3
FIGURE 15.1 Creating a test cube and attaching it to a center HUD position. In parts 1 & 2 the cube is rezzed, and the
#4 face is colored to identify it. This is the default face for attachment to the screen surface. In part 3, the cube, now a
HUD, is attached to the center of the screen using the drop down menus.
297HUDs in Virtual Environments
attachment, such as the color of your new hair. Since HUDs cannot be “clicked through,” a center-based
HUD will block much of the mouse’s target area and hinder building and interactivity with environmental
objects. It is expected that this HUD will be detached soon after use so the user can see where he or she is
going or can continue what he or she was building. The next most important positions are the bottom right
and bottom left, and these are most often used for tools, weapons, and other things that game and combat
systems utilize. The player should not have to move the line of sight too far from center to nd his or her trig-
ger or spell caster, or the consequences may be too horrible to imagine. Further down in the priority-of-use
list are the drop down menu’s remaining positions: top, bottom, top left, and top right. These positions are
often used for HUDs that contain ongoing tools and systems used by the avatar, such as radar, chat language
translators, animation overrides, and such. Positioning and content of the surrounding viewer in a virtual
world game is subjective, and that can have an impact on the design you develop for your HUD. There are
several studies about the importance of positioning in the HUD [1], and much consideration should be given
regarding the possibilities for interaction when a HUD is positioned. Of course, the player/avatar in a virtual
world can always edit the position, and often does, when seeking to make a custom screen interface.
In Second Life and OpenSim, the Firestorm Viewer acts like a gaming HUD by displaying the health meter
on the top bar and many basic orientation and informational tools on the lower bar, at the very bottom edge of
the screen. The buttons for these toolbars can be customized with drag and drop on your screen until you have
a setup customized to your activities. Eventually, as you purchase content and activate the HUDs that come
with it, you will nd that there are too many HUDs on your screen. To remove one, simply right click it and
select Detach in the pie menu; it will be whisked back into your inventory. If you think you have lost a HUD,
it has most likely just attached outside the visible screen menu. Just select one of the other HUDs or attach a
simple cube prim to the center HUD position, right click on that cube, and put it into edit mode. By using the
middle mouse button, you can zoom out and nd HUDs that have been attached outside the eld of view and
return them to your inventory. Simply reverse zoom to put the frame back into the correct screen size when
you are done; the edges of the screen frame will be shown in your viewer as a white box to guide you back.
Sometimes, HUDs are heavily scripted and as such should be used with caution. When you are going to a
large gathering, special event, or a place that has lag problems, it is prudent to remove as many of your HUDs
as you can or, if possible, put them to “sleep” so they will not add lag to the sim with their running scripts.
Furthermore, an avatar that is loaded with HUDs is difcult to teleport across sim lines. It is advised that you
minimize or remove all of your HUDs if you are going to teleport around frequently.
15.2 TYPES OF HUDS
How many types of HUDs are there? Thousands—let’s explore some of the most commonly found HUD
types. Note: If you would like to do a design survey, signicant numbers of various HUDs are available on
the Second Life marketplace (https://marketplace.secondlife.com/).
Later in this chapter, you nd a project showing you how to build one of your own: a URL giver HUD that
can be customized for your favorite websites. Let’s explore the various types of HUDs, arranged by usage or
function, in the following sections.
15.2.1 animaTion oVerrides
Animation overrides can be an individual HUD or a customizable menu built into the bottom bar of the
viewer interface. The Firestorm AO (animation overrider) interface (Figure15.2) is one such HUD. The
purpose of an animation override is to provide a place for storing and deploying all the avatar animations
that go with the character you are wearing. These animations “override” the basic out-of-the-box animations
298 Virtual World Design
that come as the default settings on a standard avatar. For instance, if your avatar works as a runway model,
you would load all the animations for walking, strutting, turning, and bowing that you would need to put on
a fashion display into the animation override HUD menu of the AO interface. In this menu, you can store
sets of animations, so switching from the runway model to the pirate to the mermaid animation sets is quick
and easy. In Figure15.2, the avatar is demonstrating various stand poses that are loaded into the AO HUD.
If you are not using the Firestorm built-in AO, it is still possible to customize and augment the collection
and sequence of animations with the use of note cards or button-based menus, there are many other kinds of
AO HUDs available in the Metaverse.
15.2.2 aTTaChmenT ConTrols To CusTomize hair, CloThes, shoes, animal aTTaChmenTs
Often, the content creators like to give their customers the option of changing hair color and length, clothes, shoe
color, or even pelt and eye color of their animal characters. Given the almost-innite capacity for change in digital
content, the choices may seem limitless. Unless you are doing a fashion show or having a really bad digital
hair day, this kind of HUD would probably only be used temporarily and then detached back to the inventory.
15.2.3 ComBaT sysTems, spell CasTing, and spying
Let the battle begin. The HUDs for combat systems, spell casting, and spying are often sophisticated combi-
nations of animation overrides, object rezzers, particle generators, and sensors. They can provide your avatar
FIGURE 15.2 Screen grab from Second Life showing the range of animations that have been loaded into the Firestorm
animation overide (AO) HUD. This HUD can be accessed from the lower right bar in the Firestorm viewer.
299HUDs in Virtual Environments
with the capacity to push other avatars, deform them, create dazzling ashes of particles, and listen in on chat
conversations half a sim away. Often complex, these HUDs can take up lots of screen real estate, and they
may cause lag as well. These are not the kinds of HUDs you want to wear while teleporting.
15.2.4 games
The game HUDs can provide the player/avatar with game components, give them special powers, and let
them access other game-related qualities or objects. Sometimes, you will have to wear one just to stay
alive. For “Inland: Search for the Sy,” a game environment that Alchemy Sims built in 2010, there was
a special HUD to help guide the players. In Figure15.3, you can see how they used a full-screen HUD.
These “scanner glasses” showed a series of slide images depicting what the missing owner (Dr. Singh) had
seen just before he vanished in the game backstory and provided various clues about the game to anyone
who recovered them.
15.2.5 inViTaTions, announCemenTs, and Tour guides
The art and performance communities in virtual worlds utilize HUDs in several interesting ways. Often, for
their shows, artists will send out invitations and announcements that take the form of HUDs. Once attached
to the invitees screen, these HUDs will deliver a nice display about the event. Landmark-giving scripts can
be added to these HUDs to give the invitee direct access to the exhibit or the opening party as shown in
FIGURE 15.3 Singh’s scanner wear HUD from “Inland: Search for the Sy.” This HUD was part of the hunt-based
game in Second Life and gave clues to the wearer about the game’s back story.
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