CAD Rendering with Quadruple Precision Combined Transform
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Solution Overview
Problem
CAD systems operating with double precision face challenges in achieving accurate visibility calculations and correct clipping of features when part instances are distant from the observer, leading to incorrect rendering of two-dimensional images.
Innovation Solution
The method involves generating a combined transform in quadruple precision, which includes the transform associated with the part instance, the viewport, and the viewport planes, and then operating on this transform in double precision to intersect faces and edges with viewport planes, ensuring accurate clipping and rendering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If double precision is used for all calculations in the CAD system, then the system operates efficiently with standard computational resources, but accuracy is lost when part instances are at large distances from the observer, leading to incorrect visibility calculations and clipping
Solution Approach 1:
The patent applies different precision levels to different parts of the calculation process. Quadruple precision is used specifically for the combined transform calculation where accuracy is critical (when part instances are distant from the observer), while double precision is used for other calculations to maintain efficiency. This localized application of higher precision resolves the contradiction by optimizing accuracy only where needed rather than applying it system-wide.
Solution Approach 2:
The patent changes the precision parameter of numerical calculations from double precision (standard) to quadruple precision (enhanced) specifically for the combined transform calculation. This parameter change allows the system to maintain accuracy for distant objects while avoiding the computational overhead of using quadruple precision for all calculations, thus resolving the contradiction between accuracy and efficiency.
2Measurement precision
If quadruple precision is used for the combined transform calculation, then accurate visibility and clipping are achieved for distant part instances, but computational overhead increases
Solution Approach 1:
The patent applies quadruple precision only to the specific calculation of the combined transform where accuracy is critical for determining visibility and clipping of distant objects. Other parts of the rendering pipeline continue to use double precision, thus achieving high clipping accuracy only where needed while minimizing the overall computational overhead of using quadruple precision throughout the system.
3Area of stationary object
If the viewport is placed far from the part instances, then a broad view of the assembly is achieved, but double precision calculations become insufficient, causing features to be incorrectly clipped or determined to be on the wrong side of viewport planes
Solution Approach 1:
The patent changes the precision parameter from double to quadruple specifically for the combined transform calculation when the viewport is distant from part instances. This allows the system to maintain accurate feature position determination and clipping decisions even when the viewport covers a large area and is far from the objects being viewed, resolving the contradiction between broad viewport coverage and precision.
Data Source
AI summary
A computer-implemented method is provided for rendering, to a designer, a two-dimensional image of an assembly of part instances in a three-dimensional assembly space within a computer-aided design (CAD) system utilizing double precision to describe part assemblies. Such assemblies are considered to be distant from a nominal observer. A viewport on a two-dimensional image plane is defined, and a combined transform is defined in quadruple precision to enable the generation of clipping lines and/or clipping points. The clipping lines and clipping points clipping the faces and edges of the part instance in the assembly to the portion of the assembly that lies within the viewport.