Parametric Patch Tessellation via Vectorized Boundary Splitting
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Solution Overview
Problem
Existing methods for tessellating parametric patches in computer graphics often result in 'crack artefacts' at patch boundaries due to differences in triangle vertex points and local geometry, leading to suboptimal rendering quality and increased rendering time.
Innovation Solution
The method involves initial vectorization of boundary curves to a predetermined flatness tolerance, determining interior tessellation points, and projecting a curve onto the vectorized boundary to find a split point that ensures crack-free tessellation by matching the flatness tolerance without modifying the boundary curve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If patches are independently tessellated, then the tessellation process is simple and fast, but crack artefacts appear at patch boundaries
Solution Approach 1:
The boundary curve is segmented into linear segments through vectorisation, and split points are introduced at specific locations (endpoints and midpoints of segments). This segmentation allows the tessellation to be divided into manageable regions that can be processed independently while ensuring continuity at the boundaries, thus preventing crack artefacts while maintaining processing efficiency.
2Reliability
If vectorisation is performed to ensure boundary matching, then crack artefacts are reduced, but the number of triangles increases and rendering time increases
Solution Approach 1:
The method applies different levels of vectorisation quality to different parts of the boundary curve. Linear segments are generated with sufficient precision to prevent cracks, but without over-vectorising entire curves. Split points are strategically placed only where necessary (endpoints and midpoints), allowing interior tessellation to proceed efficiently without requiring excessive boundary precision throughout the entire curve.
3Reliability
If the boundary curve is modified to match tessellation points, then continuity is improved, but the original curve geometry is altered
Solution Approach 1:
The method introduces split points as intermediary elements on the boundary curve. These split points are derived from the vectorised boundary segments and serve as connection points for interior tessellation. The original boundary curve geometry is preserved, and the split points act as mediators that enable continuous tessellation without modifying the underlying curve definition.
Data Source
AI summary
A method of tessellating a parametric patch (610) of an object is disclosed. A boundary curve associated with the parametric patch (610) is vectorized according to a pre-determined flatness tolerance. A tessellation point associated with a first parametric value inside the parametric patch (610) is determined based on geometry of the parametric patch (610) and a tessellation step. A curve associated with the first parametric value is determined based on the geometry of the parametric patch (610) and the tessellation step. A color split point on the vectorized boundary curve is determined. The color split point is determined based on the vectorized boundary curve and the determined curve associated with the first parametric value. The parametric patch (610) is tessellated by joining the color split point and the tessellation point.