Monday, 3 August 2015

Terrain-based virtual camera tilting, and applications thereof


Terrain-Based Virtual Camera Tilting & Applications

Google has recently been awarded U.S. Patent for Terrain based virtual camera tilting and application. Systems prevailing in navigating via a three dimensional environment tends to display three dimensional data which comprises of a virtual camera defining what kind of three dimension data to display.

The virtual camera has a viewpoint based on its orientation as well as position and by changing the viewpoint of the virtual camera one can navigate through the three dimensional setting. Environmental information system could be one form of system which utilises a virtual camera in navigating through a three dimensional setting. It is a system for the purpose of storing, recovering and manipulating and display spherical three dimensional model of the Earth.

The three dimensional model could comprises of a satellite descriptions surface which could be mapped to terrain like canyons, valleys and mountains. In the terrestrial information system, the virtual camera tends to view the spherical three dimensional of the Earth’s model from various perspectives and the internal viewpoint of the model of the Earth tends to portray the satellite images though the terrain could be difficult to view. While on the other hand, ground level viewpoint of the model may portray the terrain in detail.

Method of Swooping Between Perspectives

To changeover from aerial viewpoint to a ground level perspective, U.S. Patent Application by Varadhan et all explains a method of example of swooping between perspectives, describing reduction of distance between the virtual camera as well as the target in determining a tilt value based on the condensed distance.

The virtual camera is then positioned as per the tilt value as well as the condensed distance. A method is available for swoop navigation and in cases where the terrain seems to be flat; a viewpoint which is parallel for ground could not be much interesting to a user than in instances where the terrain differs in altitude. On applying single swoop trajectory to a complete three dimensional environment which could comprise the flat as well as the rugged terrain, could lead to incidents where the swoop trajectory would not provide an optimal user experience.

Embodiment to Change Swoop Trajectory

To manage with the variation in terrain, embodiments tend to change the swoop trajectory based on the terrain inside the view of the virtual camera. A virtual camera could be positioned at an angle comparative to the upward normal vector from the target, to swoop into a target, the angle of which may be stated as a tilt angle.
As per the embodiments, the tilt angle could rise more quickly in areas of high terrain variance for instance, mountains or cities with high buildings, than in areas with less variance in terrain such as flat plains. In order to determine the level of terrain variance in an area, embodiments could weight terrain data with higher detail more deeply than terrain data with less detail.

Moreover, the tilt angle could also be varied depending on the amount of terrain variance even if the camera is otherwise static and/or the tilt angle may be varied at the time of another manoeuver rather than a swoop.