  This paper provided empirical knowledge of the user experience for using
collaborative visualization in a distributed asymmetrical setting through
controlled user studies. With the ability to access various computing devices,
such as Virtual Reality (VR) head-mounted displays, scenarios emerge when
collaborators have to or prefer to use different computing environments in
different places. However, we still lack an understanding of using VR in an
asymmetric setting for collaborative visualization. To get an initial
understanding and better inform the designs for asymmetric systems, we first
conducted a formative study with 12 pairs of participants. All participants
collaborated in asymmetric (PC-VR) and symmetric settings (PC-PC and VR-VR). We
then improved our asymmetric design based on the key findings and observations
from the first study. Another ten pairs of participants collaborated with
enhanced PC-VR and PC-PC conditions in a follow-up study. We found that a
well-designed asymmetric collaboration system could be as effective as a
symmetric system. Surprisingly, participants using PC perceived less mental
demand and effort in the asymmetric setting (PC-VR) compared to the symmetric
setting (PC-PC). We provided fine-grained discussions about the trade-offs
between different collaboration settings.
