## 1 Introduction
Navigation, object selection, and manipulation commands are commonly used in VR/AR systems and have been evaluated by researchers. The conversion of fingertip or hand position movement to the control of the velocity of self-movement in the virtual environment (VE) has been demonstrated [25; 26] as has the use of gestures for the point and selection of virtual objects [27]. For example, to select virtual objects, users preferred the index finger thrust and index finger click gestures [27]. However, the lack of feedback can have a negative impact on user input confidence and efficiency while performing gestures [28; 29]. Therefore, researchers have designed hardware, like a flexible nozzle [30] and ultrasound haptics [31], to provide feedback while using gestures in different application scenarios. Physical surfaces like tables and walls are additional ways to provide feedback for VR/AR systems, and, being ubiquitous, can provide feedback to users by mimicking interactions with a touch screen. Researchers developed the MRtouch system which affixed virtual interfaces to physical planes [32] and demonstrated that feedback from physical surfaces can improve input accuracy. Gestures can provide an unconstrained, natural form of interaction with VR/AR systems. However, gestures can differ widely in how they are performed. For example, performing large gestures that require whole arm movement can lead to shoulder fatigue and are difficult to use for extended durations [33]. Sign language interpreters who perform mid-air gestures for a prolonged period experience pain and disorders of the upper extremities [34]. To avoid fatigue, studies suggest that repeated gestures should not involve large arm movements and should avoid overexpression or over-flexing of the hand, wrist, or finger joints [34]. Microgestures, defined by utilizing continuous small hand or finger motion, have been developed to reduce the muscle load on the upper extremities associated with large and/or mid-air gestures. Microgestures can be inconspicuous and less obvious to nearby people and are more acceptable in public settings compared to large hand or arm motions [35; 36]. Single-hand microgesture sets have been proposed to interact with miniaturized technologies [37] and to grasp hand-held objects with geometric and size differences [38]. However, some of the microgestures studied could not be easily performed. For example, the gesture to use the thumb tip to draw a circle on the palm of the same hand was found to be very difficult and uncomfortable to perform. Additionally, the proposed microgesture set was designed with the forearm resting on the tabletop in a fully supinated (palm up) position, a posture that is associated with discomfort and should be avoided if performed repeatedly [34]. Although the use of microgestures for VR/AR is appealing, as yet, there is no universally accepted microgesture set developed for VR/AR systems designed with a human-centered approach [37; 38; 39; 40; 41; 42; 43; 44; 45]. Therefore, the design of a microgesture set for common VR/AR commands that are intuitive, easily recalled, and minimize fatigue and pain is warranted. The primary purpose of this study was to design a microgesture set for VR/AR following human factors and ergonomic principles that consider user interaction habits and gesture designs that minimize hand fatigue and discomfort. Additionally, to improve the wide acceptance and usability, participants from different cultural backgrounds were recruited to build mappings between microgestures and commands for the VR/AR system. The paper is organized as follows: We first describe the methodology of the study including the selection of VR/AR commands, the design of the microgestures, the pre-assignment of microgestures to the commands by experts, and the design of software for participants to assign microgestures to the commands and rate the microgesture-command sets. Next, we describe the data analyses used.