The following videos illustrate various aspects of my research. They are arranged by topic, together with details of the relevant papers. The topics are:

• Single-User Object Manipulation
• Collaborative Object Manipulation (Piano Movers' Problem)
• Collaborative Object Manipulation (Levels of Control)
• Navigation (cluttered VEs) Immersive vs. desktop interfaces; wide (144 degree) field of view; rich visual scene; real-world vs. virtual world navigation
• Navigation (physically walking through a VE)
• Navigation (virtual mazes)
• VE Sickness

Single-User Object Manipulation (the Piano Movers' Problem)

Ruddle, R. A., Savage, J. C., & Jones, D. M. (2002). Evaluating rules of interaction for object manipulation in cluttered virtual environments. Presence: Teleoperators and Virtual Environments, 11, 591-609.

Ruddle, R. A., Savage, J. C., & Jones, D. M. (2002). Implementing flexible rules of interaction for object manipulation in cluttered virtual environments. Proceedings of the ACM Symposium on Virtual Reality Software and Technology (VRST'02), 89-96.

This study investigated a variety of rules of interaction for object manipulation in cluttered virtual spaces. In the experimental task, participants moved a bulky object through two different shapes of VE. One VE contained two openings that were offset from each other, and the other contained a C-shaped section of corridor. Links to videos that illustrate the rules of interaction, and complete trials, are in the following table.

The following videos illustrate some of the rules of interaction:

• Global orientation constancy (3 Mb): Note that the orientation of the object remains unchanged when the virtual human turns around.
• Local orientation constancy (3 Mb): Note that the object turns around with the virtual human that is carrying it.
• Physical compatibility (4 Mb): The user moves their hands up and to the left, causing the object to collide with the wall. The physically compatible position is indicated by the wireline version of the object. When the user's hands moves to a new position that doesn't cause the object to collide it smoothly returns to the physically compatible position, using a rapid controlled movement algorithm.
• Inertia (2 Mb): The rate at which the object can change position and orientation is contrained to give the impression of it having a certain amount of inertia, instead of zero mass. The user moves the object, and its physically compatible position is shown as a wireline outline until the object 'catches up'. Changes of the object's actual (shaded) position and orientation are governed by a (not so!) rapid controlled movement algorithm.

These videos illustrate full trials in the two environments:

• Offset VE (5 Mb), local orientation constancy and stop-by-parts collision response (Experiment 1).
• C-shaped VE (8 Mb), local orientation constancy and stop-by-parts collision response (Experiment 1).
• Physical compatibility (6 Mb), in combination with local orientation constancy and stop-by-parts collision response (Experiment 2).
• Inertia (7 Mb), in combination with physical compatibility, local orientation constancy and stop-by-parts collision response (Experiment 2).

Collaborative Object Manipulation (the Piano Movers' Problem)

Ruddle, R. A., Savage, J. C., & Jones, D. M. (2002). Symmetric and asymmetric action integration during cooperative object manipulation in virtual environments. ACM Transactions on Computer-Human Interaction, 9, 285-308.

Ruddle, R. A., Savage, J. C., & Jones, D. M. (2002). Symmetric and asymmetric action integration during cooperative object manipulation in virtual environments. Interactions, 9(6), 9-10.

Ruddle, R. A., Savage, J. C., & Jones, D. M. (2002). Verbal communication during cooperative object manipulation. Proceedings of the ACM Conference on Collaborative Virtual Environments (CVE'02), 120-127.

Pairs of participants, each controlling a different virtual human, moved a bulky object through two different shapes of VE. One VE contained two openings that were offset from each other, and the other contained a C-shaped section of corridor. Participants' actions were integrated using two different rules of interaction. One of these only allowed the synchronised component of participants' manipulations to take place, and the other allowed the mean. In each video, the view seen by Participant 1 (controlling the virtual human that is wearing the blue hat) is shown on top, and the view seen by Participant 2 (virtual human wearing the red hat) is shown below. The white line seen on the floor at the end of each video is the finish line. Due to an oversight in data recording, the wireline feedback that participants saw while manipulating the virtual object is not shown in the videos. Neither video contains sound.

• Offset VE video (6 Mb)
• C-shaped VE video (12 Mb)

Collaborative Object Manipulation (Levels of Control)

Ruddle, R. A., Savage, J. C., & Jones, D. M. (2003). Levels of control during a collaborative carrying task. Presence: Teleoperators and Virtual Environments, 12, 140-155.

Participants collaborated with an autonomous virtual human to carry a long pole along a defined path. Three experiments were used to investigate the effects of different levels of control (building on the pioneering work of Broadbent), obstacles, and tethered vs. human's-eye views. The following videos illustrate the interaction conditions used in the experiments.

• Sticky-small (3 Mb) condition of Experiment 1.
• Attached hand (3 Mb) condition of Experiment 1. Note how the participant doesn't now have to devote their visual attention to looking at their hand.
• Rigid arm (3 Mb) with square obstacles, each of which is only passable on one side (Experiment 2).
• Elastic arm (3 Mb) with circular obstacles, all of which are passable on both sides (Experiment 2).
• Tethered viewpoint (2 Mb), using rigid arm and square obstacles (Experiment 3). The participant's viewpoint is tethered to 'their' virtual human (the transparent one, on the right)
• Tethered viewpoint (3 Mb), using elastic arm and circular obstacles (Experiment 3).

Sticky-small interface (Experiment 1)	Human's-eye view (Experiment 2)	Tethered view (Experiment 3)

Navigation (cluttered VEs)

Ruddle, R. A., & Jones, D. M. (2001). Movement in cluttered virtual environments. Presence: Teleoperators and Virtual Environments, 10, 511-524.

This research studied the effects of different metaphors for movement in small (room-sized) but cluttered VEs. The most important finding was that participants frequently had great difficulty performing an exhaustive search of the environment (checking each of the 16 blue-topped cylinders).

Participants' task was to find the 8 targets (white squares) that were positioned on the 16 blue-topped cylinders (half the cylinders were decoys). Video

Follow-on research used the same task to study the effects of visual scene fidelity, field of view and physical vs. abstract movement on navigation.

Lessels, S., & Ruddle, R. A. (2004). Changes in navigational behaviour produced by a wide field of view and a high fidelity visual scene. Proceedings of the 10th Eurographics Symposium on Virtual Environments (EGVE'04), 71-78. Aire-la-Ville, Switzerland: Eurographics Association.

Lessels, S., & Ruddle, R. A. (2005). Movement around real and virtual cluttered environments. Presence: Teleoperators and Virtual Environments, 14, 580-596.

	Video of the low-fidelity VE used in the Presence paper
	Video of the high-fidelity VE used in the Presence paper

Navigation (physically walking through a VE)

Ruddle, R. A., & Lessels, S. (2006). For efficient navigational search humans require full physical movement but not a rich visual scene. Psychological Science, 17, 460-465.

This paper proves the dramatic benefit to navigation that is produced when participants physically walk through a virtual world. The study used a navigational search task, conducted in a room-sized space. If we can perfect walking interfaces that can be used in large-scale spaces then we will finally solve the well-known problems of disorientation and getting lost that many people suffer from when they navigate in VEs.

Rich visual scene	Walking interface (the virtual cylinders are spread over the empty floor)	Impoverished visual scene
VR lab walking interface video

Navigation (virtual mazes)

Ruddle, R. A., & Péruch, P. (2004). Effects of proprioceptive feedback and environmental characteristics on spatial learning in virtual environments. International Journal of Human Computer Studies, 60, 299-326.

Participants navigated oblique and orthogonal virtual mazes. In Experiment 1, navigation was performed using desktop and head-mounted displays. Experiment 2 investigated the effect of orthogonality and a defined (colour-coded) perimeter. Experiment 3 used 'fog' to investigate the effect of extended lines of sight and corner markers (landmarks).

	Experiment 1: Layout of one of the oblique VEs. The user starts near the aircraft and travels to the cup. Video
	Experiment 2: Oblique VE layout, with coloured perimeter. The perimeter and interior walls are pink and green, respectively. The user starts near the aircraft and travels to the cup, starting with the perimeter on their right. Other parts of the perimeter can be seen at the end of the corridor where they stop to look around. Video
	Experiment 2: Orthogonal VE layout, with coloured perimeter. The user starts near the aircraft and travels to the cup, which appears out of the fog when the user moves. Video
	Experiment 3: Orthogonal VE layout, with coloured perimeter and fog. The user travels from the fork to the flower, starting with the perimeter on their right. En-route the house appears out of the fog. Video
	Experiment 3: Orthogonal VE layout, with coloured perimeter. The user travels from the fork to the flower, starting with the perimeter on their right. The house 'pops' out of the scene at the same distance as it would have emerged from the fog in that condition. Video
	Experiment 3: Orthogonal VE layout, with corner markers. One of these (the banana) can be seen in the distance at the start of the video, and another (the TV) can be seen later on. The user travels from the fork to the flower. Video

VE Sickness

Ruddle, R. A. (2004). The Effect of Environment Characteristics and User Interaction on Levels of Virtual Environment Sickness. Proceedings of IEEE Virtual Reality (VR'04), 141-148.

This paper reports VE sickness data gathered in a number of our studies. Videos illustrating some of these studies are shown below.

Navigation in cluttered, room-sized VEs. Video	Navigation in a virtual maze. Video
Collaborative carrying with a human's-eye viewpoint. Video	Collaborative carrying with a tethered viewpoint. Video
A pursuit tracking task. Video	Rotating virtual objects using a prop interface. Video