U.S. Patent No. 8,411,092: 2D imposters for simplifying processing of plural animation objects in computer graphics generation
Issued April 2, 2013, to Nintendo Co. Ltd.
Filed/Priority to June 14, 2010
This Nintendo patent uses clever 2D tricks to emulate 3D models and reduce graphics complexity.
U.S. Patent No. 8,411,092 (the ‘092 patent) relates to efficiently achieving seemingly 3D effects with 2D imposters of plural objects. The ‘092 patent details a method in computer animation and graphics generation of projecting 3D objects onto 2D viewing planes for display. When two 3D models are moving in a virtual space they are both animated and rendered, by a processor and a 3D graphics processor. With the ‘092 patent, when the processor detects that they are overlapping it substitutes a 2D imposter model instead of the two 3D object models; the imposter representing both models. The common 2D imposter model is used to generate and render an animation of the objects onto a 2D viewing plane. The ‘092 patent is advantageous to graphics processing for video games by reducing graphics complexity and conserving memory and processing resources. The ‘092 patent is by no means the only instance of 2D graphics feigning 3D by projecting onto 2D planes; U.S. Patent No. 10,987579 uses such planes to lessen the burden on devices lacking powerful 3D rendering engines.
The technology herein involves use of 2D imposters to achieve seemingly 3D effects with high efficiency where plural objects such as animated characters move together such as when one character follows or carries another character. A common 2D imposter or animated sprite is used to image and animate the plural objects in 2D. When the plural objects are separated in space, each object can be represented using its respective 3D model. However, when the plural objects contact one another, occupy at least part of the same space, or are very close to one other (e.g., as would arise in a situation when the plural objects are moving together in tandem), the animation system switches from using plural respective 3D models to using a common 2D model to represent the plural objects. Such use of a common 2D model can be restricted in some implementations to situations where the user’s viewpoint can be restricted to be at least approximately perpendicular to the plane of 2D model, or the 2D surface on which the combined image is texture mapped can be oriented in response to the current virtual camera position.
- A method that in use is performed by a computer animation and graphics generation system of the type including a processor, a 3D graphics processor coupled to said processor, and a memory coupled to at least the processor, said 3D graphics processor projecting 3D objects onto a 2D viewing plane for display, said method comprising: defining, in the memory, a first 3D model representing a first moving object in a 3D virtual space; defining, in the memory, a second 3D model representing a second moving object in the 3D virtual space; using the processor and the 3D graphics processor to animate and render the first 3D moving object onto the 2D viewing plane for display; using the processor and the 3D graphics processor to animate and render the second 3D moving object onto the 2D viewing plane for display; with the processor, determining whether said first and second 3D moving objects overlap in the virtual 3D space; if the processor determines said first and second 3D moving objects overlap in the virtual 3D space, the processor substituting use of a common 2D imposter model instead of the first and second 3D models, the common 2D imposter model simultaneously modelling both of said overlapping first and second 3D moving objects; and using the common 2D imposter model to generate and render onto the 2D viewing plane an animated image of said first and second moving objects wherein the first moving object moves in front of the second moving object.