2D vs. 3D2.1D Successes3D Success Stories3D Failures3D AmbiguityInformation AvailabilityEmpirical ResultsHierarchical DataCone Tree & Cam TreeCone TreePerspective WallXML3DXML3D Empirical Study3D or not 3D2D Navigation3D NavigationOutput DevicesCoupled Input/OutputSummarySpatial MemorySlide 212D vs. 3D Spatial MemorySlide 23Slide 24Slide 25Representation MattersInformation Visualization Success3D GuidelinesAdam PhillippyMichael SchatzCMSC 838SApril 4th, 20052D vs. 3D3D2.1D 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 metaphor3D 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 cognition3D 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 IssuesInterface Issues3D 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 resolveInformation AvailabilitySmallman, 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 depthCone 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 displaysPerspective 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 hierarchyRisden, 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. 2000XML3D 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 freedom1. Up / Down2. Left / Right3. Rotate XYInput controlsMouse (2)Arrow keys (2)3D Navigation6 degrees of freedom1. 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 ReferenceOutput DevicesFlat monitorStereoscopic“3D” glassesRelative motionKinetic depthMotion parallaxEye trackingHead mountedRetinal displaysHolographicCoupled 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 sufferedSummary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 accessibleC. 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 FavoritesSummary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 filtersG. 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 interfaces2D 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