Swimming Across the Pacific: A Virtual Swimming Interface
Tzu-Pei Grace Chen∗, Yuichiro Kinoshita, Yasufumi Takama, Sidney Fels, Kenji Funahashi†2 and Ashley Gadd
Human Communication Technologies Laboratory
Dept of ECE, UBC, CANADA http://hct.ece.ubc.ca
2 Center for Information and Media Studies,

Nagoya Institute of Technology, Nagoya, JAPANtual swimmer, making it appear as if the virtual avatar is swimming
forward.
The virtual avatar can be adjusted so that the arms, legs and torso
match every participant. This calibration is done using known configurations of the participant as well as measurements combinedwith the eight measured points from the trackers.

Figure 1: The SAP apparatus

As swimming takes place, waves are shown at the sea surface plane.
We use recurrence relations to solve the partial differential equation
for the 2D wave as often done in standard practice. We approximate
the volume of the swimmer with bounding boxes to improve performance and determine when they intersect any of the water grids as
they move. When they intersect, the height of the water grids is set
to the same as the bounding box. Then waves are made and propagated. If the height is over a pre-defined threshold value and/or theswimming avatar’s motion interferes with waves, some particles are
made in the air to simulate splashing. As the splashing water particles fall down onto the water surface, the water grids are set to theappropriate height according to the wave model.

Conclusion
We have created a new locomotion interface for swimming andfloating in a virtual ocean in a VR environment as part of our Swimming Across the Pacific (SAP) artwork [sap ]. The artwork is motivated by Alzek Mischeff’s Swimming Across the Atlantic [Misheff1982] performed in 1982. In the SAP artwork, we swim across thePacific Ocean using the swimming apparatus in an airplane rather
than across the ocean in an ocean liner as Misheff did.

The Technology
SAP provides an exciting and fun swimming apparatus for the expert performer and the novice. It is a locomotion interface comparable to Sarcos Treadport [Hollerbach et al. 2000], Trike [Allisonet al. 2000] and Peloton Bicycling Simulator [Carraro et al. 1998].
The swimmer is suspended in a real swimming apparatus but navigates in a virtual Pacific Ocean environment. The apparatus, an 8ft
x 8ft x 8ft wooden frame, may resemble a torture-chamber but it isactually very comfortable to be suspended in. The use of bungee
cords adds buoyancy, while sand bags counterbalance the swimmer’s weight and adds inertial resistance to the swimmer’s kicking actions. Swimmers wear a minimal amount of equipment (atracked HMD, a hang-gliding harness, and wrists and ankle bands
for securing 8 position sensors) such that he or she is hindered as
little as possible during virtual swimming. Figure 1 inset depicts
the swimmer in the sap apparatus.
The virtual environment comprises a sky hemisphere, a sea surface
plane, an ocean floor plane, a virtual avatar and various lighting fordifferent times of the day. Figure 1 provides a snap shot of the virtual environment. The sky hemisphere is texture-mapped with moving clouds. And the ocean floor plane has a rugged plane, texturemapped with rocks. Both planes are animated to move past the vir∗ tzupei, yuichiro, yasufumi, gadd, ssfels@ece.ubc.ca† kenji@center.nitech.ac.jp

SAP is a novel technology inspired by performance art and built
for virtual reality. The advantage of making such locomition interface is to increase the variety of possible VR applications. The
experience is fun even for non-athletes and hydrophobes because
swimming actually takes place in a controlled air space, insteadof in water. The SAP virtual swimming system provides cradlelike comfort for users while engaging them in the exciting virtualaquatic navigation.

References
A LLISON , R. S., H ARRIS , L. R., J ENKIN , M., P INTILIE , G.,R EDLICK , F., AND Z IKOVITZ , D. C. 2000. First steps witha rideable computer. In Proceedings of the Second IEEE International Conference on Virtual Reality, 169.
C ARRARO , G. U., C ORTES , M., E DMARK , J. T., AND E NSOR ,J. 1998. The Peloton bicycling simulator. In Proceedings of theThird Symposium on Virtual Reality Modeling Language, ACMPress, New York, SIGGRAPH, SIGCOMM, 63–70.
H OLLERBACH , J. M., X U , Y., C HRISTENSEN , R., AND JACOB SEN , S. C. 2000. Design specications for the second generation
SarcosTreadport locomotion interface. In Proceedings of ASME
Dynamic Systems and Control Division, vol. 69, 1293–1298.
M ISHEFF , A. 1982. Swimming Across the Atlantic. Ciesse Piumini,Milano.
Swimming
Acrossthe
http://hct.ece.ubc.ca/research/sap.

Pacific

website.