Vection is the illusion of self-motion, usually induced by a visual stimulus. It is important in virtual reality because inducing it in motion simulations can lead to improved experiences. We examine linear and circular vection in commodity level head-mounted displays. We compare the experience of circular vection induced through a real world stimulus, an optokinetic drum, with that experienced through a virtual stimulus. With virtual stimuli, we also compare circular vection with linear horizontal and linear vertical vection. Finally, we examine circular and linear vection in more naturalistic virtual environments. Linear vection was induced more rapidly than any other type, but circular vection occurs more rapidly with a real world stimulus than a virtual one. Our results have practical application and can inform virtual reality design that uses head-mounted display technology and wishes to establish vection. Circular vection can be induced easily and rapidly through visual mechanisms that have been known since Mach [1]. We have an optokinetic drum that is capable of inducing compelling circular vection that works in almost all people we have tested in it. The goal of this project is thus twofold: (1) to see how well and how reliably vection can be induced in virtual reality with commodity-level HMDs as compared to real-world stimuli, and (2) to see if compelling vection could be comparably induced when the stimuli are complex naturalistic scenes, not abstract optic flow patterns.