Multi-resolution geometry

Abstract

A system, method, and apparatus is disclosed for creating a three-dimensional visual representation of an object having multiple resolutions by retrieving a vertex list for the object, determining a collapse order for the vertices identified in the vertex list, reordering the vertices identified in the vertex list responsive to the determined collapse, order, and creating a vertex collapse list responsive to the collapse order, where the vertex collapse list specifies, for a target vertex, a neighbor vertex to collapse to. The vertex list may comprise 3D coordinates of vertices without referring to other vertex attributes or, in alternate embodiments, the vertex list may refer to other vertex attributes such as colors or normals. A runtime manager is disclosed which dynamically manages the polygon counts for objects and frames based upon the location, velocity, and area of the object. Polygon counts are also adjusted based upon a target frame rate and a target polygon count. A system is also disclosed for continuous transfer of data across a remote connection in which different levels of resolution are transmitted individually.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation of U.S. patent application Ser. No. 09 / 243,099, filed on Feb. 2, 1999, which claims priority under 35 U.S.C. §119(e) from U.S. provisional patent application serial No. 60 / 089,794, filed on Jun. 18, 1998.DESCRIPTION OF THE RELATED ART[0002]1. Field of the Invention[0003]This invention relates to the field of generating three-dimensional graphics; more specifically, to the field of generating multiple resolutions of an object in a three-dimensional environment.[0004]2. Background of the Invention[0005]Realistic three-dimensional object rendering for use in games and other software applications has been the goal for software and hardware makers in the computer industry for years. However, numerous problems prevent the achievement of realistic three-dimensional object rendering on a typical user's home computer.[0006]Three-dimensional graphics use polygons to create the object to be rendered. These polygons...

AI Technical Summary

Benefits of technology

[0011]In accordance with the present invention, an apparatus, system, and method is disclosed for producing realistic rendering of a 3D object while minimizing the use of user system resources and maximizing fidelity without sacrificing speed. The invention produces a continuous level of detail of an object using vertex merging responsive to the location of the object on the screen and other factors, thus eliminating the object popping effect. As the object moves towards the background, and therefore requires less polygons in order to provide a realistic rendering, vertices of the object are merged together in a manner designed to cause the least visual distortion. As the vertices are merged, polygons within the object are eliminated, thus lowering the polygon count of the object continuously as it moves farther and farther away from the screen. As an object moves towards the screen, vertices are added to the object, adding polygons to the object and thus providing a more realistic representation of the object as it grows close to the user and fine details become necessary. Thus, at any given moment, every object on the screen only has as many polygons as is required to provide a realistic rendering of the object. No polygons are being unnecessarily drawn, and thus optimum use is being made of the user's system. No object-popping effects are created as polygons are added or removed from the object on a continual basis based on the object's movement in the 3D environment.

[0012]Additionally, the invention requires only one version of the object to be authored and stored on the user's system, thus minimizing the impact on system resources. One vertex list is used which preferably specifies the highest level of detail, and the system in accordance with the present invention is able to then generate the continuous level of detail of the object for display on the screen. Also, the system advantageously increases and decreases the resolution of the objects on the fly. Thus, as only the current level of detail being displayed is stored, minimal use of memory is required. By storing certain minimum information which is determined prior to run-time to guide the resolution changes, the resolution changing is performed at run time at optimal speed. Another benefit of the present invention is its ability to allow a developer to tweak the vertex merging in accordance with the developer's own preferences. Finally, the invention automatically adjusts the amount of polygons in a screen responsive to the capabilities of a user's system, providing an optimal image for every user. In one embodiment, the invention monitors the system to determine the frame rate at which the frames are being rendered, and adjusts the total amount of polygons allowable on the screen at one time accordingly.

[0013]Additionally, a target frame rate may be set, which allows the user to specify the speed at which the scenes should be rendered. The present invention then dynamically adjusts the total amount of polygons to ensure the frame rate is maintained. Alternatively, the invention allows a polygon count to be specified, and then ensures that this amount of polygons is always on the screen, regardless of the frame rate.

Problems solved by technology

However, numerous problems prevent the achievement of realistic three-dimensional object rendering on a typical user's home computer.

However, the more polygons used to create an object, the more computations required to render the object, thus slowing down the speed at which the object is rendered.

The resolution of this problem is not easy.

Thus, the developer must assume the user's processor is slow and is therefore capable of only rendering a small number of triangles per second.

This solution, however, pleases neither the user with a low-end computer nor the user with the high-end computer.

The user with the low-end computer will most likely still have images which are slow and choppy, because the developers are unwilling to completely sacrifice realism, and the user with a high-end computer will have images which appear artificial and robotic because the application is not designed to take advantage of the high-end machine's greater processing power.

In fact, on some high-end systems, the application will be too fast to play or interact with because the polygon count is too low.

Another problem facing the developer is the fact that the same object requires more detail when closer to the screen than it requires if it is in the background.

However, the most detailed version of the object cannot always be used to render the object because the application will require too much computing power to quickly and smoothly render images on the screen.

If too many polygons are used for each object, thus providing the necessary realism for the object when it is close to the screen, then the processor will not be able to achieve the above minimum frame rate required for smooth rendering.

Typically, only three or four levels are used because storage of multiple versions of each object to be rendered can consume too much of the user's system resources.

There are several drawbacks to the level of detail methodology.

First, this method has a large impact on system resources, as described above.

Second, when transitioning from one level to another, an effect known as object popping occurs.

The higher detailed version of an object is abruptly rendered as the object moves towards the screen, and “pops” out at the viewer, ruining the 3D immersive qualities of the application.

The level of detail method also requires extra authoring of each version of the object, requiring more time from the developer.

Level of Detail also does not address the lowest common denominator problem described above.

Thus, the highest level of detail cannot contain too many polygons or the image will appear slow and choppy on the low-end user's computer.

Again, this image will also appear angular and robotic on the high-end user's computer, as it does not take advantage of the high-end computer's greater processing power.

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