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US5214752A
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Point placement method for use in a three-dimensional automatic mesh generation system
Assignee: International Business Machines Corp
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Filing: 1991-01-22
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Granted: 1993-05-25
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Expires: 2011-01-22
Abstract
Abstract A method for producing a set of points for a mesh of finite elements for a body to be analyzed, the body exhibiting boundaries and faces. The method comprises the steps of: producing an initial mesh of elements for the body, each element having a plurality of vertices and edges; for each vertex in a first subset of the vertices, finding points of intersection (POI) between a sphere of radius R, centered at a vertex being considered, and the boundaries and edges; determining if a found POI is either on or within the boundaries of the body and exhibits more than a minimum clearance distance from the boundaries, and vertices, any such POI being classified as a selected POI; inserting a selected POI in the initial mesh; and repeating the aforementioned steps for all POI's in the first subset and then proceeding to succeeding subsets of vertices until all POI's in all subsets have been considered.
Inventors
- 👤 Siavash N. Meshkat
- 👤 James M. Ruppert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 14:39
CPC Classifications
G; G06; G06T; G06T17/00; G06T17/20
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
162 words
A method for producing a set of points for a mesh of finite elements for a body to be analyzed, said body exhibiting boundaries and faces, said method comprising the steps of: a. producing an initial mesh of elements for said body, each said element having a plurality of vertices and edges; b. for each vertex in a first subset of said vertices, finding points of intersection (POI's) between a sphere of radius R, centered at said vertex, and said boundaries and edges; c. determining if a found POI is either on or within boundaries of said body and if so, exhibits more than a minimum clearance distance from said boundaries and vertices, if both conditions are met, said POI is classified as a selected POI; d. inserting a selected POI in said initial mesh; and e. repeating steps b-d for all POI in said first subset, and then proceeding to succeeding subsets of said vertices, until all subsets have been considered.
Claim 2
Independent Claim
162 words
A method for producing a set of points for a mesh of finite elements for a body to be analyzed, said body exhibiting boundaries and faces, said method comprising the steps of: a. producing an initial mesh of elements for said body, each said element having a plurality of vertices and edges; b. for each vertex in a first subset of said vertices, finding points of intersection (POI's) between a sphere of radius R, centered at said vertex, and said boundaries and edges; c. determining if a found POI is either on or within boundaries of said body and if so, exhibits more than a minimum clearance distance from said boundaries and vertices, if both conditions are met, said POI is classified as a selected POI; d. inserting a selected POI in said initial mesh; and e. repeating steps b-d for all POI in said first subset, and then proceeding to succeeding subsets of said vertices, until all subsets have been considered.
Claim 3
Dependent Claim
63 words
The method as recited in claim 1 wherein said method comprises the added step of: a1. assigning to each subset of said vertices, a priority value from a range of values spanning from highest to lowest, and performing steps b-e on all vertices in a subset exhibiting a higher assigned priority, before vertices are considered in a subset having a lower assigned priority.
Claim 4
Dependent Claim
49 words
The method as recited in claim 2 wherein said method comprises the further step of: d1. assigning a priority value to said selected POI which is a next lower priority than the priority value assigned to the subset of which the vertex at the center of said sphere belongs.
Claim 5
Dependent Claim
44 words
The method as recited in claim 3 wherein said method comprises the additional step of: e1. incrementing the value of radius R to a higher value when said method proceeds to consideration of a next subset of vertices having an assigned lower priority value.
Claim 6
Dependent Claim
58 words
The method as recited in claim 4 wherein said method comprises the additional step of: c1. for any POI found which is within said boundaries of said body and exhibits more than a minimum clearance distance from other vertices, but not from a boundary, projecting said POI onto said boundary and classifying such POI as a selected POI.
Claim 7
Dependent Claim
34 words
The method as recited in claim 4, wherein step (a) comprises the additional step of: a2. assigning to a high priority subset of said vertices, any vertex which is close to a neighbor vertex
Claim 8
Dependent Claim
33 words
The method as recited in claim 4, wherein step (a) comprises the additional step of: a2. assigning to a high priority subset of said vertices, any vertex where a boundary condition is specified.
Claim 9
Dependent Claim
37 words
The method as recited in claim 4, wherein step (a) comprises the additional step of: a2. assigning to a high priority subset of said vertices, any vertex located at a sharp corner or turn of said body.
Claim 10
Dependent Claim
24 words
The method as recited in claim 4 comprising the further step of: d2. revising said mesh of elements to include said inserted, selected POI.
Claim 11
Dependent Claim
65 words
The method as recited in claim 9 wherein each said element is a tetrahedron, said method comprising the further steps of f. calculating a volume to area ratio for each tetrahedron created by step d2; and g. adding a point locally to create new tetrahedra having larger volume to area ratio if said calculated volume to area ratio in step f falls below a threshold.
Claim 12
Dependent Claim
20 words
The method as recited in claim 10 wherein said added local point falls within a circumsphere surrounding a said tetrahedron.
Claim 13
Dependent Claim
42 words
The method as recited in claim 11 wherein said added local point is placed within said circumsphere and at a maximum distance from an adjacent boundary, unless such distance is smaller than a threshold, in which case another local point is selected.
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