Trimmed Surface Display Processing Using Sight-Line Single-Valued Areas
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Solution Overview
Problem
Conventional techniques for displaying trimmed surfaces in CAD systems require excessive calculation time due to the need for determining intersections with trim curves for each triangle, especially when dealing with large numbers of triangles.
Innovation Solution
A computer-implemented display processing method that identifies sight-line single-valued areas and generates mask data for these areas, allowing for efficient drawing and intersection determination, and in cases where the viewpoint is within a volume, simplifies the processing by treating the entire base surface as a single-valued area, reducing the need for calculating outer and inner loop intersections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional tessellation method is used to display trimmed surfaces, then the display can be achieved using standard triangle rendering, but the calculation time becomes excessively long due to determining intersections with trim curves for each triangle
Solution Approach 1:
The patent divides the base surface into multiple sight-line single-valued areas, where each area is processed independently. This segmentation allows the system to avoid calculating intersections with trim curves for all triangles across the entire surface, instead only processing triangles within each single-valued area, thereby significantly reducing calculation time while maintaining display accuracy.
Solution Approach 2:
The patent performs preliminary classification of triangles into sight-line single-valued areas before performing intersection calculations. By pre-identifying which triangles belong to which single-valued area and determining their visibility status in advance, the system eliminates the need for repeated intersection determination for hidden or irrelevant triangles, thus reducing overall calculation time.
2Device complexity
If the entire base surface is processed as a single area, then processing is simplified, but intersection calculations with trim curves still require excessive time when there are large numbers of triangles
Solution Approach 1:
The patent segments the base surface into multiple sight-line single-valued areas, each of which can be processed independently with simplified logic. This segmentation maintains low processing complexity within each area while avoiding the excessive calculation time that would result from processing all triangles globally, as the system only performs intersection calculations for triangles within visible single-valued areas.
Solution Approach 2:
The patent applies partial processing by focusing computational resources only on triangles that are visible and belong to sight-line single-valued areas, rather than performing exhaustive intersection calculations for all triangles in the base surface. This partial action approach reduces calculation time by eliminating redundant computations for hidden or irrelevant triangles.
3Measurement precision
If mask data is generated for each triangle, then precise control of displayed pixels is achieved, but the processing time increases significantly
Solution Approach 1:
The patent merges the processing of multiple triangles that belong to the same sight-line single-valued area into a single processing step. By generating mask data for entire single-valued areas rather than for each individual triangle, the system maintains precise pixel control while significantly improving processing speed through batch processing of visually related triangles.
Solution Approach 2:
The patent applies partial processing by generating mask data only for triangles that are visible and belong to sight-line single-valued areas, rather than generating mask data for all triangles in the base surface. This selective approach maintains pixel control precision for visible regions while reducing overall processing time by eliminating redundant mask generation for hidden triangles.
Data Source
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AI summary
A display processing method for displaying a shape of an object including a trimmed surface generated based on a base surface includes: dividing the base surface into plural triangles ; generating a loop polygon for loops including an outer loop for defining an outer shape of the trimmed surface and an inner loop provided, in the outer loop, depending on the shape of the obj ect; identifying one or plural sight-line single-valued areas, each of which satisfies a condition that mapping onto a projection surface is bijection, includes plural triangles, and is an area on the base surface, based on a positional relationship between a viewpoint and the base surface; generating, for each of the one or plural sight-line single-valued areas, mask data that is data for controlling whether or not display is performed for each pixel from the sight-line single-valued area and the loop polygon; generating image data on the projection surface for each of the plural triangles; and performing a drawing processing from the mask data and image data.