It is our great pleasure to welcome you to the second ACM Symposium on Spatial User Interaction - SUI'14. This event focuses on the user interface challenges that appear when users interact in the space where the flat, two-dimensional, digital world meets the volumetric, physical, threedimensional (3D) space we live in. This considers both spatial input as well as output, with an emphasis on the issues around the interaction between humans and systems. The goal of the symposium is to provide an intensive exchange between academic and industrial researchers working in the area of SUI and to foster discussions among participants. The SUI symposium was held October 4-5, 2014, in Honolulu, USA.
The call for papers attracted 62 submissions from Asia, Europe, Australia, and North and South America in all areas of Spatial User Interaction research. The international program committee consisting of 19 experts in the topic areas and the three program chairs handled the highly competitive and selective review process. Every submission received at least four detailed reviews, two from members of the international program committee and two or more from external reviewers. The reviewing process was double-blind, where only the program chairs as well as the program committee member, who was assigned to each paper to identify external reviewers, knew the identity of the authors. In the end, the program committee accepted overall 18 (11 long papers plus 7 short papers) out of 62 submissions, which corresponds to an acceptance rate of 29% in total. Additionally, 25 posters complement the program and appear in the proceedings. Furthermore, several demos were presented at the symposium. The topics range from spatial interaction techniques, gestures, vision in 3D space, spatial applications, to interaction with multi-touch technologies and spatial interaction in augmented reality. We hope that these proceedings will serve as a valuable reference for Spatial User Interaction researchers and developers.