Computer graphics processing and selective visual display system – Computer graphics processing – Three-dimension
Reexamination Certificate
1999-01-13
2001-04-24
Nguyen, Phu (Department: 2671)
Computer graphics processing and selective visual display system
Computer graphics processing
Three-dimension
Reexamination Certificate
active
06222551
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to graphics processing and display systems and, in particular, to those capable of rendering and displaying three dimensional (3D) models and objects.
BACKGROUND OF THE INVENTION
In a conventional client-server structure or arrangement the server is used to store a 3D model and to deliver it to connected clients. The clients then display the model and support user interaction with the model. For large models containing many polygonal facets, the geometric description of the model (using, for example, vertices, faces and normals) can be larger than a rendered image of the model. The server is thus relied on to render images of the model and to transmit the rendered images to the connected clients.
At the client, an interactive 3D graphics application typically requires a frequent adjustment of viewpoint with respect to the 3D model to be rendered. For example, the user may inspect a 3D model by virtually rotating the model in a manner similar to manually inspecting a physical model that is held in the hand.
Currently, the use of 3D graphics on mobile computing devices is hampered by several factors, including computational power and bandwidth-limited connections to servers. Since 3D models of non-trivial complexity may require a large amount of data to display, the time required to transmit the required data through a bandwidth-limited connection can be objectionable to the user, and/or may make it very difficult or impossible to operate in a real-time, interactive manner. For example, if the user can manipulate a mouse or trackball to change the viewpoint of a displayed model in just a few seconds, but if it requires a server some tens of seconds to transmit an updated image of the model from the new viewpoint to the mobile computing device, then the user's perception of an interactive graphics session is detrimentally affected.
While it is known that server-side rendering has been used in some systems, one significant disadvantage with conventional server-side rendering approaches is that the user is only presented with one particular view of the model. To obtain another view, the user has to request the server to render the model from a new viewpoint. However, choosing that desired viewpoint is often difficult because there is no means to specify the viewpoint by directly manipulating the model.
OBJECTS AND ADVANTAGES OF THE INVENTION
It is a first object and advantage of this invention to provide an efficient and effective solution to the viewpoint selection problem.
It is a further object and advantage of this invention to provide a technique to address the problems inherent in using 3D graphics on a mobile computing device.
It is a further object and advantage of this invention to provide methods and apparatus for improving a client/server arrangement when processing, transmitting and displaying 3D models during the execution of an interactive 3D graphics application.
SUMMARY OF THE INVENTION
The foregoing and other problems are overcome and the objects and advantages of the invention are realized by methods and apparatus in accordance with embodiments of this invention.
There is provided a method and apparatus for operating a client/server graphics processing system of a type that includes a display for displaying images to a user and a user input device whereby a user is enabled to specify a view direction from which to view a model of interest. A scene or model may comprise several independent objects (connected components).
A first step, executed at the server entity, renders a plurality of views (e.g., six views) of the model and transmits the plurality of views to the client entity. A next step, executed at the client, maps individual ones of the plurality of views onto individual ones of a plurality of faces of a structure, and displays the structure on the display. The structure may be a cube or a box, where a box is intended to encompass three dimensional structures that have both square and rectangular bounding faces. Other structure shapes can be used as well. The plurality of views may be texture mapped onto the faces of the structure. In response to the user manipulating the user input device, a next step executed at the client causes a manipulation of the structure displayed on the display for specifying a particular view direction relative to the model. By example, the box can be rotated about one or more of its axes, causing various ones of the views mapped on the box's faces to become visible to the user. Further in response to user input device, the client sends an indication to the server of the user-specified view direction, whereafter the server renders an image of the model, from the user-specified view direction, and transmits the rendered image back to the client for display to the user. The step of rendering a plurality views of the model may operate to first render those views that would be currently visible to the user.
REFERENCES:
patent: 5448686 (1995-09-01), Borrel et al.
patent: 6088040 (2000-07-01), Oda et al.
Martin Ioana M
Schneider Bengt-Olaf
Cameron Douglas W.
International Business Machines - Corporation
Nguyen Phu
Perman & Green LLP
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