Gradual Transitions into VR

Every virtual reality (VR) experience includes some way of immersing a user into the VR system. Some work has demonstrated that the staging of the experience and introduction of a user to the system can impact her subsequent sense of presence. In theme parks a similar concept is successfully used. For example, prior to a ride in a roller coaster passengers have to cross dungeons or fairy tale worlds to mentally prepare for the experience. The concepts of a gradual transition from the real to the virtual world and vice versa have already been introduced in some research projects.

For example, Slater et al. have performed an experiment in the so-called “VirtualAnte” room, where subjects entered a virtual replica of the laboratory. In their experiment, subjects moved through a door to a new virtual location and carried out the main experimental task. Slater et al. also proposed to use a virtual head-mounted display (HMD) within the virtual world in such a way that when the user puts on the virtual HMD she is transferred to another virtual world. After taking off the last HMD, the user is returned to the virtual environment (VE) from where she was transferred before. This procedure provides a recursive HMD-based virtual world.

Transitional techniques might also be used in CAVE environments. For example, Steed et al. augmented a common four-sided (three-walled) CAVE with a white curtain. This curtain was used for projection, and the users could see a virtual CAVE with avatars inside. As a user walked through the curtain into the CAVE, an avatar appeared on the curtain, representing the user.

The main idea of a transitional environment is to provide users with an intermediate state between the real world and the target VE. In the most common applications of such environments, the transitional environment is basically a virtual world which simulates the physical environment in which the user resides during the VR experience; usually such a transitional environment is given by a virtual 3D model of a VR laboratory.

We modeled a transitional environment of our VR laboratory as a set of texture-mapped polygons. The texture maps were obtained from a mosaic of digital photographs of the walls, ceiling and floor of the laboratory. All floor and wall fixtures were represented true to original as detailed, textured 3D objects, e.g., door knobs, furniture and computer equipment. When the user dons the HMD she sees a virtual replica of the laboratory space.

The idea of the transitional environment is to start the VR experience in a virtual replica of the surrounding physical space to accustom users to the characteristics of VR, e.g., latency, reduced field of view or tracking errors, in a known environment. Tracked movements in the physical laboratory are mapped one-to-one to the transitional environment so that users can move through the virtual replica and touch walls like in the real world. After a certain time period, the user may enter the remote virtual environment, where the actual virtual 3D world is presented. Due to this start in a familiar environment, a gradual transition to the virtual world becomes possible.

The video on the right side shows a transitional environment used for gradual transitions in the Arch-Explore user interface.

Recent experiments have shown that transitional environments in combination with virtual portals can enhance a user's sense of presence.

VIDEOS

"Arch-Explorer" (.mov, 74 MB)