Smart transparency for virtual objects

A method performed by a head mounted display (HMD) device employed by a user occupying a physical environment, the HMD device having one or more processors and supporting rendering of a virtual reality environment that includes virtual objects, comprising:

• placing, using the one or more processors coupled to the HMD device, a fade volume that surrounds the user, the fade volume having a near shell that is proximate to the user and a far shell that is distal to the user, in which the near shell is positioned a radial distance from the user such that the near shell is distinct from the user;
• determining, using the one or more processors and one or more sensors coupled to the HMD device, a location of a virtual object with respect to the near and far shells by tracking the user's location within the virtual reality environment;
• and
• rendering, using the one or more processors, the virtual object with transparency when it is located between the near and far shells, the transparency increasing as the virtual object becomes closer to the near shell,
• wherein the HMD device is configured to continuously render the virtual reality environment so that no part of the physical environment or the user is displayed on the HMD device.