A system, comprising: a controller comprising one or more processors; and a head-mounted display, HMD, configured to display a 3D virtual view to a user, wherein the HMD comprises: left and right displays for displaying frames including left and right images to the user's eyes to provide the 3D virtual view to the user; a plurality of sensors configured to collect information about the user and the user's environment and provide the information to the controller, wherein the plurality of sensors includes: one or more cameras configured to capture views of the user's environment; one or more world mapping sensors configured to determine range information for real objects in the user's environment; and one or more eye tracking sensors configured to track position and movement of the user's eyes; wherein the controller is configured to: determine adjusted depths at which to render one or more of the real objects in the user's environment captured in the views by the one or more cameras in the 3D virtual view based on the range information from the one or more world mapping sensors such that nearby objects may be re-rendered to be smaller in the display to help the user in avoiding the objects when moving about in the environment; and render frames for display by the HMD that include the one or more real objects in the captured views of the user's environment rendered at the adjusted depths for the one or more real objects and virtual content composited into the captured views of the user's environment based at least in part on the range information from the one or more world mapping sensors and the position and movement of the user's eyes as tracked by the one or more eye tracking sensors. a controller comprising one or more processors; and a head-mounted display, HMD, configured to display a 3D virtual view to a user, wherein the HMD comprises: left and right displays for displaying frames including left and right images to the user's eyes to provide the 3D virtual view to the user; a plurality of sensors configured to collect information about the user and the user's environment and provide the information to the controller, wherein the plurality of sensors includes: one or more cameras configured to capture views of the user's environment; one or more world mapping sensors configured to determine range information for real objects in the user's environment; and one or more eye tracking sensors configured to track position and movement of the user's eyes; left and right displays for displaying frames including left and right images to the user's eyes to provide the 3D virtual view to the user; a plurality of sensors configured to collect information about the user and the user's environment and provide the information to the controller, wherein the plurality of sensors includes: one or more cameras configured to capture views of the user's environment; one or more world mapping sensors configured to determine range information for real objects in the user's environment; and one or more eye tracking sensors configured to track position and movement of the user's eyes; one or more cameras configured to capture views of the user's environment; one or more world mapping sensors configured to determine range information for real objects in the user's environment; and one or more eye tracking sensors configured to track position and movement of the user's eyes; wherein the controller is configured to: determine adjusted depths at which to render one or more of the real objects in the user's environment captured in the views by the one or more cameras in the 3D virtual view based on the range information from the one or more world mapping sensors such that nearby objects may be re-rendered to be smaller in the display to help the user in avoiding the objects when moving about in the environment; and render frames for display by the HMD that include the one or more real objects in the captured views of the user's environment rendered at the adjusted depths for the one or more real objects and virtual content composited into the captured views of the user's environment based at least in part on the range information from the one or more world mapping sensors and the position and movement of the user's eyes as tracked by the one or more eye tracking sensors. determine adjusted depths at which to render one or more of the real objects in the user's environment captured in the views by the one or more cameras in the 3D virtual view based on the range information from the one or more world mapping sensors such that nearby objects may be re-rendered to be smaller in the display to help the user in avoiding the objects when moving about in the environment; and render frames for display by the HMD that include the one or more real objects in the captured views of the user's environment rendered at the adjusted depths for the one or more real objects and virtual content composited into the captured views of the user's environment based at least in part on the range information from the one or more world mapping sensors and the position and movement of the user's eyes as tracked by the one or more eye tracking sensors.