Hermite Gregory Patch Watertight Tessellation Memory
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Solution Overview
Problem
Conventional graphics processing units face inefficiencies in memory utilization for watertight tessellation of displaced subdivision surfaces due to the need for substantial additional data storage for auxiliary tangent surfaces, limiting their usage in graphics processing.
Innovation Solution
The method employs Hermite Gregory patches, which are parametrically continuous in position and partial derivatives, allowing for concise vertex parameter representation and efficient sharing between patches, reducing memory requirements by eliminating the need for auxiliary tangent surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If auxiliary tangent surfaces are used for watertight tessellation of displaced subdivision surfaces, then the tessellation accuracy and watertightness are improved, but the memory utilization efficiency deteriorates due to substantial additional data storage requirements
Solution Approach 1:
The patent extracts and eliminates the auxiliary tangent surface data structure from the system, achieving watertight tessellation through direct evaluation of displacement maps at patch vertices without requiring separate tangent surface storage, thereby resolving the memory efficiency problem while maintaining tessellation accuracy
Solution Approach 2:
The displacement map serves multiple functions simultaneously: it provides both the geometric displacement information and the tangent plane orientation data needed for watertight tessellation, eliminating the need for separate auxiliary tangent surfaces and improving memory utilization
2Manufacturing precision
If auxiliary tangent surfaces are stored for displaced subdivision surfaces, then the quality of watertight tessellation is improved, but the data storage requirements increase substantially
Solution Approach 1:
The patent merges the tangent surface information into the existing displacement map data structure, combining multiple functions into a single data source that provides both position and orientation information, thereby reducing overall data storage requirements while maintaining tessellation quality
Solution Approach 2:
The patent changes the parameter representation by evaluating displacement maps at specific parametric coordinates (patch vertices) rather than storing explicit tangent surfaces, achieving the same tessellation quality with reduced data storage through mathematical evaluation
3Measurement precision
If conventional techniques for watertight tessellation are used, then the tessellation accuracy is maintained, but the memory utilization becomes inefficient, limiting usage in graphics processing units
Solution Approach 1:
The displacement map serves itself by providing both geometric and tangent information through a single data structure, eliminating the need for separate auxiliary tangent surfaces and enabling more efficient memory utilization in graphics processing units while maintaining tessellation accuracy
Data Source
AI summary
One embodiment of the present invention sets forth technique for watertight tessellation in a displaced subdivision surface. A subdivision surface is represented as a novel parametric quad patch that is continuous with respect to position (C0) and partial derivatives (C1) along boundaries as well as interior regions. The novel parametric quad patch is referred to herein as a Hermite Gregory patch and comprises a Hermite patch augmented to include a pair of twist vector parameters per vertex. Each pair of twist vectors is combined into one twist vector during evaluation, according to weights based on proximity to parametric boundaries. Evaluation yields an approximation mesh comprising a position for each vertex and a corresponding normal vector for the vertex. Displacement is performed based on the approximation mesh and a displacement map to generate a displaced approximation mesh that is reflective of the displaced subdivision surface.