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Adam PhillippyMichael Schatz
CMSC 838SApril 4th, 2005
2D vs. 3D3D
2.1D Successes
Modest use of 3D to add highlights to 2D interfaces:
Raised/Depressed Buttons
Overlapping Windows & Shadows
Icons that resemble real-world objects
Now a standard component of desktop metaphor
3D Success Stories Natural 3D Visualizations
Medical Imagery, Architectural Drawing, Computer Assisted Design, Scientific Simulations
Continuous variables, volumes, surfaces, inside and outside, left and right, below and above are intrinsically meaningful.
Game Environments First person shooters, role playing
fantasy, virtual 3D environments Increasingly rich social contexts
based on social cognition
3D Failures
Air-Traffic Control Systems (ambiguity) Hierarchical Browsing (occlusion, navigation) Line & Bar Charts (distortion, ambiguity)
Digital Library (poor search, linking) Desktops & Workspaces (orientation) Web Browsing (screen space)
3D I
ssue
sIn
terf
ace
Issu
es
3D Ambiguity
Projective ambiguity 3D on a 2D display creates
ambiguity in all 3 dimensions
2D shadows help disambiguate x,y position
Orientation ambiguity 3D models provide limited
information Other icons may be
necessary to resolve
Information Availability
Smallman, H. S., St. John, M., Oonk, H. M., and Cowen, M. B. 2001. Information Availability in 2D and 3D Displays. IEEE Comput. Graph. Appl. 21, 5 (Sep. 2001), 51-57.
Empirical Results
Controlled experiment with 32 users performing search tasks across interfaces
Confirmed results of a prior study (orange), but that study compared across information visibility styles in addition to 2D-3D differences.
2D is clear winner when comparing with consistent information visibility (green).
Hierarchical Data
• Rooted, Directed relationships• File Systems, Organization Trees, …
• Traditional Node-link diagrams require space proportional to number of children at different levels• Overall aspect ratio grows exponentially with depth
Cone Tree & Cam Tree
“The clearest win in this technology is interactive animation. It is easy to demonstrate that animation shifts cognitive load to the
human perceptual system.”
Robertson, G. G., Card, S. K., and Mackinlay, J. D. 1993. Information visualization using 3D interactive animation. Commun. ACM 36, 4 (Apr. 1993), 57-71.
Cone Tree
Issues Occlusion Navigation Orientation
Contrast with SpaceTree
Same animation benefits
TreeMap 1,000,000 node
displays
Perspective Wall
Details are presented with overview via fisheye-like zoom for linear data
Sharp distortion at wall boundaries.
Robertson, G. G., Card, S. K., and Mackinlay, J. D. 1993. Information visualization using 3D interactive animation. Commun. ACM 36, 4 (Apr. 1993), 57-71.
XML3D
Visualize the link structure for web sites using hyperbolic zoom.
Support web content creators placing new content into existing hierarchy
Risden, K., Czerwinski, M., Munzner, T., Cook, D. An initial examination of ease of use for 2D and 3D information visualizations of Web content, International Journal of Human-Computer Studies, v.53 n.5,
p.695-714, Nov. 2000
XML3D Empirical Study
Controlled Experiment with 16 users and 4 tasks.
Measure performance relative to 2D hierarchical displays (Windows Explorer).
Statistically significant performance improvement for search tasks when category is present.
3D or not 3D Input
Mice offer only 2 degrees of freedom Output
Screens are planar User cognition
Naturally operate in 3D world Awareness, perception, reasoning, and judgment
Costs and benefits?
2D Navigation 3 degrees of freedom
1. Up / Down
2. Left / Right
3. Rotate XY
Input controls Mouse (2) Arrow keys (2)
3D Navigation 6 degrees of freedom
1. Forward / Back2. Left / Right3. Up / Down4. Pitch (transverse axis)
5. Yaw (normal axis)
6. Roll (longitudinal axis)
Input controls Mouse + arrow keys (4) Flight stick (5) 3D Mouse (6) Body Reference
Output Devices Flat monitor
Stereoscopic “3D” glasses
Relative motion Kinetic depth Motion parallax
Eye tracking Head mounted Retinal displays Holographic
Coupled Input/Output Ware and Franck
Find path of length 2 between 2 nodes 2D projection
~26% error 3D stereo with tracking
~8% error Timings roughly similar
Limited interaction Head/hand coupled Motion was effective, but
timing suffered
Summary Positives
3D information visualization has promise Eye tracking for parallax effect Stereo for depth
Missing features 3D input device for rotation
Negatives Uncomfortable for user Hardware not widely accessible
C. Ware and G. Franck, “Evaluating Stereo and Motion Cues for Visualizing Information Nets in Three Dimensions,” ACM Trans. Graphics, vol. 15, no. 2, 1996, pp. 121-139.
Spatial Memory Robertson’s Data Mountain
Leverage spatial abilities while keeping interaction simple Faster and more accurate than IE4 Favorites
Summary
Positives Leverages spatial and image memory
Users remembered their layout after several months! Simple navigation (point and click) Keeps user orientated at all times Limits occlusion and clutter Keeps text readable via pop-ups 3D audio enhances sense of depth
Missing features Auto alignment X-ray vision Dynamic filters
G. Robertson et al., “Data Mountain: Using Spatial Memory for Document Management,” Proceedings of UIST’98, 1998, ACM Press. 153-162.
2D vs. 3D Spatial Memory Where did I…
Leave Firefox? 2D window manager
Park my car? 2D (2½D) parking lot
Park my spaceship? 3D space
Which is the most effective for memory?
2D vs. 3D Spatial Memory Cockburn and McKenzie
Compare 2D vs. 2½D vs. 3D Data Mountain Both virtual and physical interfaces
2D vs. 3D Spatial Memory Users surprised by their spatial memory Subjective ratings
Preferred physical over virtual Physically least cluttered: 2D > 2½D ≈ 3D Physically quickly found pages: 2D > 2½D > 3D 3D felt “cluttered” and “inefficient”
Summary Skeptical of 3D document retrieval
As dimensionality increased Speed decreased User preference decreased
Spatial memory clearly effective But...
3D hindered retrieval, even in the physical world
A. Cockburn, B. McKenzie, “Evaluating the Effectiveness of Spatial Memory in 2D and 3D Physical and Virtual Environments,” Proc. ACM Computer-Human Interaction Conf. Human Factors in
Computing Systems, ACM Press, 2002, pp.203-210
Representation Matters
W. Ark, et al., “Representation Matters: The Effect of 3D Objects and a Spatial Metaphor in a Graphical User Interface,” Proc. Human-Computer Interaction Conf. People and Computers XIII,
Springer-Verlag, 1998, pp.209-219.
Information Visualization Success Success is often due to design features that make the interfaces
even better than reality
Interface controls are as important as the graphics display
Metrics help guide design
Usability testing is essential
“… it might be more important to fight for two versus three clicks than to debate 2D versus 3D.”
Shneiderman, B. 2003. Why Not Make Interfaces Better than 3D Reality?. IEEE Comput. Graph. Appl. 23, 6 (Nov. 2003), 12-15.
3D Guidelines
Use occlusion, shadows, perspective carefully
Minimize the number of navigation steps for users to accomplish their tasks
Keep text readable
Avoid unnecessary visual clutter, distractions, contrast-shifts and reflections
Simplify user and object movements
Organize groups of items in aligned structures to allow rapid visual search
Enable users to construct visual groups to support spatial recall
Allow teleportation, x-ray vision