A computer implemented method of navigating a digital representation of a spatial environment by a user in which a portion of the digital representation is rendered by a rendering computer system for visualization by the user. The method including accessing a digital model of the spatial environment including a specification of each of a plurality of virtual resources in the spatial environment, each specification identifying at least a location of a resource in the spatial environment and at least one trigger criterion for determining when a resource is accessed by the user; monitoring the satisfaction of trigger criteria for the plurality of virtual resources; and responsive to the monitoring, determining the portion of the digital representation for rendering by the rendering computer system for visualization by the user.