ISO/TS 23301:2021 STEPジオメトリ視覚化サービス | ページ 6

3.1

boundary representation solid model

B-rep

type of geometric model in which the size and shape of a solid is defined in terms of the faces, edges and vertices which make up its boundary

[SOURCE:ISO 10303-42:2019, 3.1.2.5]

3.2

constructive solid geometry

CSG

type of geometric modelling in which a solid is defined as the result of a sequence of regularized Boolean operations operating on solid models

[SOURCE:ISO 10303-42:2019, 3.1.2.12]

3.3

derived geometry

geometric representation generated from another representation

Note 1 to entry: The derivation is realized by actions such as using another representation method, another format, approximations, simplification

3.4

converted geometry

result of changing the data format of a geometry

Note 1 to entry: The import and export operations in a CAD system produce converted geometry.

Note 2 to entry: Converted geometry is a kind of derived geometry (3.3) .

3.5

design intent

intentions of the designer of a model with regard to how it may be instantiated or modified

Note 1 to entry: The aspects of design intent relevant to ISO 10303-108 are concerned with the information represented in the parameters and constraints associated with a model. More generally, design intent also includes the procedural or construction history of a model, which is the subject of ISO 10303-55. All aspects of design intent influence the behaviour of a model under editing operations.

[SOURCE: ISO 10303-108, 3.7.10, modified — Changed"this part of ISO 10303" to"ISO 10303-108" in Note 1 to entry].

3.6

geometry data set

serialized representation of geometry data which can be exchanged between two systems

Note 1 to entry: The geometry data set can be instantiated into a single file, a set of files, a web service payload or the result of a database query.

3.7

geometry service

web-service supporting retrieval of geometry-related data

3.8

level of detail

LOD

description of detail and extent of geometric model information

3.9

native geometry

native CAD

data format used to write to memory using the authoring CAD application's CAD kernel

3.10

original geometry

geometry as defined by a modeler (human being) in a CAD tool using CAD authoring functions based on mathematical constructs

Note 1 to entry: The original geometry is the first initial geometry construction that holds the design intent.

Note 2 to entry: This is also often referred to as native CAD (3.9) . However, a native CAD is in fact referring to the native CAD kernel and CAD format of the CAD tool manipulating the geometry. It therefore can also be any geometry derived from another CAD format.

Note 3 to entry: Geometry as initially authored in a CAD/ modelling application using that tool's geometric modelling system, operations, and database. The author's design intent (3.5) as well as the characteristics and artefacts of the application's implementation of geometric and solid modelling algorithms, are present in the original geometry, thus distinguishing it from"exact geometry". Original geometry can take on many forms, e.g. B-rep (3.1) , CSG (3.2), hybrid, tessellated, and be modelled using many modelling paradigms, e.g. procedural, explicit, dual, parametric features with construction history.

Note 4 to entry: While often misused and interchanged for each other, original geometry is distinguished from native geometry (3.9) .

3.11

procedural model

generative model

history-based model

model described in terms of the operation of a sequence of procedures (which may include the solution of constraint sets), as opposed to an explicit or evaluated model which captures the end result of applying those procedures

Note 1 to entry: Although procedural models are outside the scope of ISO 10303-108, they are defined here to make an important distinction between two fundamentally different modelling approaches. The present resource is intended to be compatible with ISO 10303-55, which provides representations for the exchange of procedurally defined models.

[SOURCE: ISO 10303-108, 3.7.28, modified — Changed"this part of ISO 10303" to"ISO 10303-108"].

3.12

product and manufacturing information

PMI

non-geometric attributes in 3D CAD and Collaborative Product Development systems necessary for manufacturing product components and assemblies

Note 1 to entry: PMI may include geometric dimensions and tolerances, symbols, notes, surface finish, and material specifications.

[SOURCE:ISO 10303-62, 3.1.3.2]

3.13

tessellated geometry

geometry composed of a large number of planar tiles, usually of triangular shape

Note 1 to entry:Tessellated geometry is frequently used as an approximation to the exact shape of an object.

[SOURCE:ISO 10303-42, 3.1.2.47]

3.14

3D visualization

visual presentation on a screen or another media of graphical and textual three-dimensional representations of a set of data representing an object, information or results of a computational process in order to facilitate capture of the understanding of the object, for visual information sharing with users and sometimes to promote decision process by a human looking at the data visualized in a medium

[SOURCE:ISO 14306:2017, 3.1.1]