DESIGN PRINCIPLES FOR DESKTOP 3D USER INTERFACES

Case Movie Plaza

Marja Tyynelä, Timo Jokela, Minna Isomursu

Department of Information Processing Science, University of Oulu, Rakentajantie 3, Oulu, Finland

Petri Kotro, Olli Mannerkoski

Valkeus Interactive Ltd, Pohjolankatu 4, Rovaniemi, Finland

Keywords: 3D user interfaces, Design principles, Usability, User experience, Interaction, Orientation, Navigation

Abstract: 3D user interfaces in desktop applications are becoming more common and available to all users. However,

not many guidelines are available to support desktop 3D user interface design. We derived a set of design

principles from the practices of a company specialized to 3D graphics and user interfaces and made a

prototype to evaluate these principles. The results of our evaluations show that some of the principles - on

the structure of the space, navigation and interaction - helped users while some others did not have the

desired impact. We conclude that design guidelines for 3D user interfaces can be derived from the

designers’ practices but research is needed to make principles more specific and to test their affect more

precisely.

1 INTRODUCTION

In recent years the amount of digital information has

increased. How to manage, browse, explore, and

retrieve all this vast amount of information has

become an important and challenging research topic.

One approach to solve this problem is to use

hree dimensional, 3D, desktop user interfaces

instead of the 2D desktop, which has been the de

facto standard in most operating systems and

desktop applications during the past 20 years.

There are studies suggesting that the 3D

etaphor would help users to remember the location

of the information objects, because it utilizes natural

human capabilities, such as spatial memory

(Robertson et al. 1998; Robertson et al. 2000).

The 3D user interfaces are often associated with

virtual reality

systems utilizing head-mounted-

displays (HMD) and data gloves (Barrilleaux, 2001).

Desktop 3D user interfaces, however, require only

one special device: a 3D-accelerated video card.

These cards are common nowadays, but the use of

the desktop 3D is still rare outside gaming and

scientific communities (Chin, 2002).

Earlier 3D technology has been available only

r specialists who have been using Computer Aided

Design (CAD) or similar applications in their work,

but today, after the web has made 3D applications

popular amongst ordinary users, it is likely that the

desktop 3D user interfaces will become more

common (Barrilleaux, 2001). Thus, it is important to

understand and pay attention to how to design usable

3D desktop interfaces (Poupyrev, 1995). However,

not many guidelines are available to support desktop

3D user interface design (Herndon et al. 1994).

1.1 Usability Problems

The lack of guidelines and design principles has lead

to poor design, which has caused usability problems

in 3D user interfaces. Earlier, when 3D technologies

were not so common, the problems related, among

other things, to insufficient performance of the

computers. Users did not get immediate feedback, so

the interaction was difficult (Carey et al. 1994).

Nowadays these problems are not relevant, because

the development of 3D graphics standards, like

Virtual Reality Modelling Language (VRML), and

3D-accelerated video cards has increased these

performance related problems (Li & Ling, 2002).

Nowadays the problems relate to users perceptive

and cognitive skills. For example there have been

difficulties in orientation in some 3D user interfaces

Tyynelä M., Jokela T., Isomursu M., Kotro P. and Mannerkoski O. (2005).

DESIGN PRINCIPLES FOR DESKTOP 3D USER INTERFACES - Case Movie Plaza.

In Proceedings of the Seventh International Conference on Enterprise Information Systems, pages 85-90

DOI: 10.5220/0002554100850090

 SciTePress

(Chin, 2002) and users have experienced interfaces

with 3D more cluttered and less efficient than their

2D counterparts (Cockburn & McKenzie, 2002).

Designing navigation methods for 3D user interface

is a challenge for designers. Many studies suggest

that using the navigation methods provided by 3D

virtual space is difficult for users (Elliot &

Bruckman, 2002; Hendricks et al. 2003). Also

moving virtual camera, view to the virtual space, can

cause problems. The camera can “get stuck” in

certain parts of the environment (Li & Ting, 2002)

or user may feel that the environment moves

towards him/her when user is supposed to feel that

he/she is moving (Chin, 2002).

In summary, the typical problems in 3D user

interfaces are related to orientation, incoherence,

navigation and handling the virtual camera.

Designers need design guidance that would address

the challenge of creating 3D user interfaces that are

easier to use.

1.2 Research setting

The guidelines for two-dimensional world do not

take into account special characteristics of the three-

dimensional world. A designer has to make

decisions on elementary 3D design aspects such as

how to organize the space, how to use light and

textures on different surfaces and objects, and how

to let the users orientate themselves in a 3D world.

Our hypothesis is that if users were able to

perceive the structure of the virtual space better and

if they would be provided with natural navigation

methods they would orientate themselves better and

the user interface would be easier to use. The

purpose of this article is to preliminary evaluate a set

of design principles that address the specific design

challenges of the 3D user interfaces. We derived the

design principles from the practices of a company

specialized to 3D graphics and user interfaces. The

designers of the company have knowledge also from

architecture – designing real world spaces, and

cultural philosophy – the cultural knowledge of how

people interact with the environment. The

experience of this company’s designers is

transformed for the first time to design principles.

Material from the earlier studies that the company

had performed, including interviews, discussions

and written material was used during the

development of the principles.

Following the design principles, we built a 3D

prototype called Movie Plaza. Then we carried out a

set of qualitative usability evaluations, in which we

studied how these principles worked and, in more

general, how the users experienced 3D user

interface.

In the next section, we describe the design

principles. Then we describe shortly how those

principles were used to build our prototype, the

Movie Plaza. Thereafter, we draw conclusions on

how well those principles worked according to the

user evaluations.

2 DESIGN PRINCIPLES

The design principles (DP) fall into three categories:

the structure of the space, lighting and textures, and

navigation and interaction.

2.1 The Structure of the Space

The design of the structure of space aims at

providing the user with a possibility to use spatial

memory efficiently in memorizing the location of

user interface objects and outline the boundaries of

accessible space.

DP1: Four orthogonal main directions

should be used in the basic spatial layout.

Vast majority of real world buildings are based on

four orthogonal main directions. Orthogonal co-

ordinate system is fast to perceive and easy to

remember. Humans have a bodily co-ordinate

system that has four directions: human body has

clear front and back, and symmetric left and right

directions. These directions are so obvious for us

that we do not have to count them to be able to

utilize them in our memory and decision making

processes. Our hypothesis is that users would easily

understand the four main directions and be able to

know their orientation in space at all situations.

Using symmetrical order and shapes of geometric

primitives would enhance this. Utilizing this ability

in 3D user interfaces would help users to understand

the layout of the space and orientate themselves in

the space with a small cognitive load.

DP2: If there is a lot of data to be visualized,

the space should be divided into several

elevations rather than only one.

Effective usage of computer screen requires

effective use of z-axis in the spatial design. The idea

behind this design solution is simply to imitate the

idea of multi-floor spaces. The specific advantage of

this principle would be the effective use of the

screen area. Many of 3D user interface applications

have only one level, a model probably adopted from

the open landscapes. If lots of data must be visible, it

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means that objects are “far” and users may have

difficulties in seeing them clearly. In addition,

navigation and moving from one side of the space to

the other with standard mouse and keyboard is time

consuming (Elliot & Bruckman, 2002). Allocating

the data on several elevations would mean more

effective use of the screen space. Our hypothesis is

that if the screen is used effectively for displaying

the relevant data, there is less need for movement

and navigation is more effective. Users also

understand the structure of the space and thus they

are able to orientate themselves.

2.2 Lighting and Textures

Lighting is used for drawing the attention of the user

as well as giving information about the directions for

the user. In real world, the same principles are used

for marking pathways and to grab attention to

important and relevant details.

DP3: There should be one main light source

used throughout the space giving a sense of

directions. The general lighting should be

neutral, and the shadows of the general

lighting should be used throughout the space.

Some people and many animals are known to use

sunlight direction as a navigational tool in real world

navigation. These light effects have an important

meaning in orientation. The hypothesis is that in 3D

user interfaces the use of light effects would also be

important for orientation. Simulation of sunlight that

comes from one direction and creates lights and

shadows to the walls should be used to help

orientation inside the space.

DP4: Spotlights should be used to highlight

important and interesting places and

landmarks.

Spotlights are used to emphasize points of interest.

Several specific pointed lights should be used to

highlight important and interesting places and to

imply of warm and inviting atmosphere. Our

hypothesis is that users are able to see where to pay

attention with the help of the spotlights and thus,

they are able to understand the structure of the space

better.

DP5: The grids on surfaces should be used

for emphasizing the structure.

In 3D user interfaces grids should be used for

emphasizing the structure of space in order to give

for the user a better understanding of distances and

scales of the space. Grids are also one way to make

more effective perspective impression. Our

hypothesis is that the grids help user to better

understand the structure of the space.

DP6: Textures of objects other than the ones

containing the actual information should be

simple and minimalist in detail.

Our hypothesis is that surfaces that surround the

information should not divert user’s attention from

the actual information but to give an understanding

of the space and structure in order for the user to

find the information.

2.3 Navigation and Interaction

Navigation and interaction design principles are

used for providing the user with the possibility to

interact with the system using the metaphors of the

three-dimensional worlds.

DP7: Interaction should be direct, which

means that objects are manipulated by direct

actions. Indirect user interface components

such as menus and scroll bars should not be

used.

The 3D user interface makes possible and

understandable to use real world direct interaction,

which means that operations can be done for

example by pointing and clicking the objects

directly. Our hypothesis is that direct interaction

decreases users’ cognitive load and makes the

choices easier and more natural to the user. This

should help users to navigate easily.

DP8: Browsing - i.e. looking the environment

- and moving in it should be different

operations.

Our hypothesis is that if natural ways to move from

the real world are exploited in the 3D user interface

by differentiating browsing and moving, it helps

users to navigate in the environment. The hypothesis

is based on assumption that users are able to utilize

their real world experiences and thus, the user feels

moving methods natural and easy. This should help

users to navigate easily and also moving the virtual

camera should be easy.

DP9: Moving should be restricted to natural

movements.

In real world gravity restricts movements so that it is

impossible to float in the air or sink down through

the floor. In some virtual reality applications user is

able to have six degrees of freedom (6dof), which

DESIGN PRINCIPLES FOR DESKTOP 3D USER INTERFACES - Case Movie Plaza

makes them able to incline camera view in

correlation to Z-axis or to turn around in horizontal

or vertical direction. This may cause difficulties for

users, because they may lose their orientation. Our

hypothesis is that in 3D user interfaces moving

should be restricted so that user easily understands

the limitations and possibilities of the environment.

This is best done by restricting users’ moves so that

free flying in the air is not possible and users’ are

not able to turn upside down. This principle should

help users to navigate easily and also moving the

virtual camera should become easy.

3 THE MOVIE PLAZA

PROTOTYPE

The Movie Plaza environment was developed to

demonstrate and evaluate the principles outlined in

the previous section. The goal was to design a 3D

user interface that would be easy to use and that

would enable users to achieve their objectives in a

natural and enjoyable way. This means utilizing

natural human abilities, such as spatial memory.

The Movie Plaza is a gallery where a user can

browse movie information. The user interface is

illustrated in Figure 1.

3.1 Applying the design principles in

the prototype

The Movie Plaza was designed using the preceding

ten design principles. The usage of the principles is

described in the following.

DP1: The virtual space in the Movie Plaza

strongly emphasizes the four orthogonal main

directions in the spatial layout. The space consists of

four equally long and high walls, so the space is

shaped like a cube. Four movie cylinders are

symmetrically organized to these walls. Geometric

primitives, cube and cylinder, are used to enhance

the effect of the four main directions.

DP2: The virtual space of the Movie Plaza

composes of three elevations, and so the whole

screen is used effectively for displaying essential

information: movie posters. There is, however, some

empty space between categories so that user can

Figure 1: The Movie Plaza.

separate the groups from each other and the visual

image is clear.

DP3: General lighting that helps in orientation is

implemented in the Movie Plaza by placing two

windows on one wall for illuminating the space.

With the help of this one main light source, users

should have better understanding of their orientation.

The windows are illustrated in Figure 1.

DP4: The contrast of cool-toned general lighting

and warm-toned spotlights is used to illuminate the

movie cylinders and draw the focus to the movies.

Warm light spots are also used for providing user

feedback: light is switched on when user points the

cylinder and switched off when the user moves the

cursor away from the cylinder. The tone of lighting

used in the cylinders is warm so that cylinders would

look inviting.

DP5: In the Movie Plaza walls, floor and roof

are consistently covered with 3x3 grids. Colors of

the grids are white and green. Thus, the visual image

is simple.

DP6: Simple textures have been used on

surfaces. Only the actual information items, i.e.

movie posters, are rich in color and detail. All other

surfaces are simple as they try not to draw user’s

attention.

Lighting is simple and light effects are not used

in textures. This is done to avoid the assumption that

the user interface provides the possibilities of real

world interaction often available in computer games.

DP7: Only buttons used in the Movie Plaza are

elevator buttons that can be used for taking the user

up or down in the space. Otherwise functions such

as getting information about movie or changing view

or viewpoint is done by moving the mouse or

pointing or clicking an object. Information window

opens when the user clicks on the poster and closes

when the user clicks on the information window.

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Figure 2: The user browses the environment with the

automatic view change.

DP8: The Movie Plaza offers two different ways

to move in the space. User can move between

different elevations by using an elevator, which

works by clicking the elevator buttons. Another way

to move is restricted flying between the categories,

which works by clicking the destination category

with a mouse. There is also two ways to browse the

environment. User can keep the left mouse button in

the bottom and move the mouse, when the view

changes in relation to mouse movements. Another

way is to move mouse to the other side of the screen

which makes the view to change automatically. With

these navigation methods users should be able to

move fluently and efficiently. View change is

illustrated in Figure 2.

DP9: In the Movie Plaza moving is limited so

that view’s Z-axis is always kept inline with the

world’s Z-axis. Also, looking up and down is natural

so that it is not possible for the user to turn up side

down and look what is behind him without turning

around. Also navigation routes are restricted so that

users are able to move only between three central

points and categories and from category to category.

Restricted flying in the air is one way to move, but

flying freely in the air is not possible.

4 EVALUATION

The evaluation of our design principles using Movie

Plaza prototype was based on qualitative usability

testing as depicted in (Dumas & Redish, 1993), i.e.

we observed how subjects were able to perform

given tasks with the prototype. We were interested

in the performance of the subjects and their

subjective experience evoked by the system. We

evaluated how the subjects liked to use the system,

what cognitive responses did the user interface

evoke, and how the design principles affected these.

Analysis was qualitative and it was based on

user comments and researchers’ observations,

interviews and video analysis. Evaluation must be

considered to be only preliminary, as we had only

six users.

Users found the test interesting. Design

principles seemed to have effect to usability,

because only few of the typical usability problems

appeared. The evaluation results are summarized in

Table 1.

User evaluation showed that most of the users

perceived the space well during the first task and

they were able to move there smoothly and

efficiently. Vertical orientation was experienced

easy. Users considered the space simple and

according to their opinion they were able to find

movies easily, although some users would have

wanted to use text-based search in search tasks.

Table 1: Summary of design principles and results.

Design

principle

Result

DP1 Positive results. Users did not get lost

and perceived the space easily.

DP2 Positive results. Users were able to

remember if a certain movie or

category was above or below them.

DP3 Negative results. Light did not help

in orientation and users lost their

orientation.

DP4 Neutral results. Lights made

categories look inviting, but did not

help in giving feedback to user.

DP5 Results suggest that simple grids

helped understanding the structure of

the space and did not draw users’

attention from more important issues.

DP6 Results suggest that textures could be

even simpler so that users do not

confuse 3D user interfaces with

games.

DP7 Positive results. Users were able

move smoothly and getting more

information about a movie was self-

explanatory.

DP8 Positive results. Users understood

immediately that moving mouse

moves their view. Most of the users

found navigation easy.

DP9 Positive results. Navigation methods

guided users to the right actions.

DESIGN PRINCIPLES FOR DESKTOP 3D USER INTERFACES - Case Movie Plaza

Horizontal orientation was experienced to be

hard, because light did not help users in orientation.

The users thought that a clear landmark for helping

in horizontal orientation would be needed, for

example a compass on the floor, windows that

would provide a view to outside world or some

object inside the space that calls users’ attention.

Some users had problems related to navigational

controls, partly because they did not get any

guidance at the beginning. Especially two older

users had difficulties in navigation tasks that may

have been derived from the fact that they had less

experience of different types of computer

applications.

Evaluation showed that users find 3D desktop

metaphor useful and also exciting. In general users’

experiences were positive and most of them said that

3D user interface could be useful in their every day

life.

5 DISCUSSION

We created a set of design principles for 3D user

interfaces. The user evaluations showed that some of

these principles would be beneficial in designing 3D

user interfaces and that these principles are a good

start for developing the design of 3D interfaces.

Although the results are preliminary, we find this

work as an important contribution. More and more

3D user interfaces are being designed but no

guidelines for designing desktop 3D user interfaces

exist.

Our research has limitations that need to be

understood. First, the study was done based on a

single prototype. The principles were implemented

in the prototype but the details of user interface

design impact on the usability, too. Thereby, the

isolation of the impact of principles from the other

design solutions is not easy.

Second, our tests were preliminary ones and of

qualitative nature. In qualitative research results are

always subjective despite that the results are based

on thorough analysis of video and written material.

The results suggest paths for further research.

The principles could cover better horizontal

orientation and logical ways of starting and ending

using the application. Standard moving methods

could be developed so that users could use different

applications after they have learned one. Another

interesting question is whether 3D user interfaces

could be an answer to the problems small 2D screens

of mobile devices.

Our research suggests, that design principles can

be derived from the existing 3D user interface

design practices, and this can result in 3D interfaces

that are easy and effective to use.

REFERENCES

Barrilleaux, J., 2001. 3D user interfaces with Java 3D,

Manning. Greenwich (CT).

Carey, R., Fields, T., van Dam, A., & Venolia, D., 1994.

Why is 3-D interaction so hard and what can we really

do about it? In SIGGRAPH’01, International

Conference on Computer Graphics and Interactive

Techniques. ACM Press, 492-493.

Chin, R., 2002. Three-dimensional file system browser.

Crossroads, 9, 1, 16-18.

Cockburn, A., & McKenzie, B., 2002. Evaluating the

effectiveness of spatial memory in 2D and 3D physical

and virtual environments. In CHI’02, Conference on

Human Factors in Computing Systems. ACM Press,

203-210.

Dumas, J.S., & Redish, J.C., 1993. A practical guide to

usability testing. Ablex Publishing Corporation.

Norwood (NJ).

Elliot, J., & Bruckman, A., 2002. Design of a 3D

interactive math learning environment. In DIS’02,

Symposium on Designing Interactive Systems. ACM

Press, 64-74.

Hendricks, Z., Tangkuampien, J., & Malan K., 2003.

Virtual galleries: is 3D better? In AFRIGRAPH’03,

Computer graphics, virtual reality, visualisation and

interaction in Africa. ACM Press, 17-24.

Herndon, K., van Dam, A., & Gleicher, M., 1994. The

challenges of 3D interaction. SIGCHI Bulletin 26, 4,

36-43.

Jordan, B., & Henderson A., 1994. Interaction analysis:

foundations and practice (IRL Report No. IRL94-

0027). Xerox Palo Alto Research Center and Institute

for Research on Learning, Palo Alto, California.

Li, T.-Y., & Ting, H.-K., 2002. An intelligent user

interface with motion planning for 3D navigation. In

Virtual Reality. IEEE. 177-178.

Poupyrev, I., 1995. Research in 3D user interfaces. The

IEEE Computer Society's Student Newsletter 3, 2, 3-5.

Robertson, G., Czerwinski, M., Larson, K., Robbins, D.,

Thiel, D., & van Dantzich, M., 1998. Data

mountain: using spatial memory for document

management. In UIST’98, Symposium on User

Interface Software and Technology. ACM Press, 153-

162.

Robertson, G., van Dantzich, M., Robbins, D.,

Czerwinski, M., Hinckley, K., Risden, K., Thiel, D., &

Gorokhovsky, V., 2000. The Task Gallery: a 3D

window manager. In CHI’00, Conference on Human

Factors in Computing Systems. ACM Press, 494-501.

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