Improved Offset Handling in Hand-centered Object Manipulation Extending Ray-casting

As Virtual Reality (VR) is becoming a readily available tool in an increasing number of fields, we see also an increasing number of non-technical users entering virtual environments (VEs). One pose manipulation technique that has the potential to be both fast and intuitive to use, is the Hand-centered Object Manipulation Extending Ray-casting (HOMER), presented first by Bowman and Hodges [1]. In this paper we take a look at how a naive implementation of HO-MER can lead to unintuitive interaction and present mathematics for avoiding this problem, by using a rotational offset of the grab vector instead of a static offset vector. Subsequently we compare the naive and rotation-based versions with respect to task completion time and number of re-grabs, and measure their respective System Usability Scale (SUS) score and Raw NASA Task Load Index (RTLX)