Topology Determination for Structured Mesh Generation

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Solution Overview

Problem

Existing methods for generating structured meshes from three-dimensional shapes often result in deformation and reduced predictability due to overly strict constraints, as they incorrectly identify non-decomposable shapes with intersections, leading to unsuitable mesh generation.

Innovation Solution

A topology determination apparatus identifies causal intersection positions causing non-decomposability, allowing for selective elimination of these intersections and dynamic adjustment of constraint conditions to generate a decomposable shape, which is then used to create a structured mesh without unnecessary deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If strict constraint conditions are applied to exclude all intersections in recognition model generation, then decomposability is improved, but mesh deformation increases and predictability decreases

Engineering Contradiction:

ImprovedecomposabilityVSAvoidmesh deformation

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent segments the set of all intersections into two categories: causal intersections (which prevent decomposability) and non-causal intersections (which do not affect decomposability). This segmentation allows selective constraint application, applying strict constraints only to causal intersections while allowing non-causal intersections to remain, thereby maintaining decomposability without unnecessary mesh deformation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different constraint qualities to different types of intersections. Causal intersections receive strict constraints to ensure decomposability, while non-causal intersections are allowed to exist without constraints. This local differentiation of constraint quality resolves the contradiction by applying constraints only where necessary.

Inventive Principle:

Principle #3Local quality

2Stability of the object's composition

If strict constraint conditions are applied to exclude all intersections, then decomposability is improved, but calculation complexity and time increase

Engineering Contradiction:

ImprovedecomposabilityVSAvoidcalculation time

Core Design Contradiction:

Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent segments intersections into causal and non-causal categories, allowing the calculation process to focus only on causal intersections when applying constraints. This segmentation reduces the number of constraints that need to be evaluated and enforced, thereby reducing calculation time and complexity while still ensuring decomposability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of applying constraints to all intersections (excessive action), the patent applies constraints only to causal intersections (partial action). This partial application of constraints is sufficient to ensure decomposability while avoiding the unnecessary computational overhead of constraining non-causal intersections.

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If all intersections are excluded to ensure decomposability, then mesh generation reliability is improved, but adaptability to complex shapes decreases

Engineering Contradiction:

Improvemesh generation reliabilityVSAvoidhandling complex shapes

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent segments intersections into causal and non-causal types, allowing reliable mesh generation for decomposable shapes while adapting to complex shapes that contain non-causal intersections. This segmentation enables the system to handle complex shapes with overlapped parts by allowing non-causal intersections while maintaining reliability through constraints on causal intersections only.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter of constraint application from a binary (all-or-nothing) approach to a selective approach based on intersection type. By changing which intersections are constrained rather than applying uniform constraints to all intersections, the system achieves both reliability for decomposable shapes and adaptability for complex shapes with non-causal intersections.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS7436407B2Topology determination, decomposable shape generation, and structured mesh generation

Publication Date: 2008.10.14 ACTIVISION PUBLISHING INC

AI summary

Enables efficient correction of topological consistency of an input three-dimensional shape approximated in a spatial graph. Structured mesh generation systems of the present invention include: a topology determination apparatus for reading shape data from a shape data storage device to determine topological consistency and outputting data for solving a problem about topological consistency; a decomposable shape generation apparatus for reading the data outputted by the topology determination apparatus, changing a constraint condition of an integer programming problem solver to execute a shape correction process and outputting corrected shape data; and a structured mesh generation apparatus for reading the corrected shape data to generate a structured mesh.