Visual realism enhances realistic response in an immersive virtual environment--part 2

Does realistic lighting in an immersive VR application enhance presence--that is, the participants' feeling that they're actually in the scene and behaving accordingly? Part 1 of this study indicated that presence is more likely with real-time ray tracing than with ray casting. However, that research couldn't separate the effects of overall illumination quality from the dynamic effects of real-time shadows and reflections. In a new experiment, 20 people experienced a scene rendered with either global or local illumination. Both conditions included dynamically changing shadows and reflections. Illumination quality didn't affect presence, so the earlier result must have been caused by dynamic shadows and reflections. Nevertheless, global illumination did result in greater plausibility--that is, participants were more likely to respond as if the virtual events were real. These results indicate that global illumination does affect participant responses and is worth the effort.