PTAB

IPR2016-00928

Electronic Arts Inc v. Infernal Technology LLC

Log In
Key Events
Petition
petition Intelligence

1. Case Identification

2. Patent Overview

  • Title: Shadow Rendering Method for Computer Graphics
  • Brief Description: The ’822 patent discloses a multi-pass method for rendering shadows in three-dimensional computer graphics. The claimed invention uses an "additive lighting" approach where a scene is first rendered from an observer's perspective, then light contributions from multiple sources are determined and stored in a light accumulation buffer, and finally combined with the observer view to produce the final displayed image.

3. Grounds for Unpatentability

Ground 1: Claims 1-10 and 39-48 are obvious over Segal.

  • Prior Art Relied Upon: Segal (a 1992 publication titled "Fast Shadows and Lighting Effects Using Texture Mapping").
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Segal, which was not considered during prosecution, disclosed a nearly identical three-pass rendering process for generating shadows. In Segal's Pass 1, a scene is rendered from the observer's perspective to generate color data and depth data (using a z-buffer). In Pass 2, which is repeated for each light source, Segal determines which pixels are illuminated by comparing the observer depth data to a "shadow map" (a z-buffer from the light's perspective) and accumulates the light from each source in a memory buffer (the pixel color field of the framebuffer). In Pass 3, the accumulated light is multiplied by the scene's surface color to produce the final image for display. Petitioner contended this process taught every limitation of independent claim 1.
    • Motivation to Combine (within Segal): Segal provided an express motivation to combine its "spotlight effect" (additive light accumulation) with its "shadow effect" (shadow mapping via depth comparison). The reference explicitly stated that "the shadow effect may also be combined with the spotlight effect" and provided figures depicting the enhanced realism of the resulting illuminated and shadowed scene.
    • Expectation of Success: A person of ordinary skill in the art (POSITA) would have had a high expectation of success in implementing the combined process, as Segal described all necessary components and illustrated the final, desired result, providing a clear technical roadmap.

Ground 2: Claims 1-20 and 39-48 are obvious over Segal in view of McReynolds.

  • Prior Art Relied Upon: Segal (as described above) and McReynolds (a 1996 SIGGRAPH course note titled "Programming with OpenGL: Advanced Rendering").
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground was presented as an alternative in the event the term "light accumulation buffer" was construed narrowly to require a memory space separate and distinct from the framebuffer. While Segal taught accumulating light in a field within the main framebuffer, McReynolds taught implementing Segal's algorithm using the OpenGL API and explicitly disclosed using a dedicated, separate "accumulation buffer" for integrating light contributions. McReynolds's buffer was distinct from the framebuffer and was specifically designed for accumulating lighting and shadowing effects.
    • Motivation to Combine: Petitioner argued a POSITA would combine Segal's rendering algorithm with the separate accumulation buffer taught by McReynolds. McReynolds explicitly cited Segal and described the same fundamental three-pass process. A POSITA would have been motivated to use the separate buffer taught by McReynolds when implementing Segal's method to gain known advantages, such as higher color precision (more bits per color component), which is critical for accurately combining light from multiple sources without artifacts—a primary goal of the Segal method.
    • Expectation of Success: The combination involved a simple design choice of substituting one known buffer type (a field in Segal's framebuffer) for another (McReynolds's dedicated buffer) to perform the exact same function of light accumulation within the same well-defined algorithm. This would have been a predictable and straightforward modification.

4. Key Claim Construction Positions

  • "light accumulation buffer": Petitioner argued this term should be construed as "a memory for accumulating the light falling on the pixels in the camera image." This construction was central to the petition's dual-ground strategy. Petitioner contended that under a Broadest Reasonable Interpretation, this term would encompass the pixel color field within the framebuffer as taught by Segal (supporting Ground 1), but also presented Ground 2 in case the term was construed more narrowly to require a memory space physically distinct from the framebuffer, as explicitly taught by McReynolds.
  • "observer data": Petitioner proposed this term encompassed "the combination of color data for a scene from the perspective of the observer, and depth data for a scene from the perspective of the observer." This was based on the patent's own description of generating a "camera image" (RGB pixel data) and a "camera depth" (a Z-buffer) during its initial rendering pass.

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1-20 and 39-48 of Patent 6,362,822 as unpatentable.