ISO 14306:2017

INTERNATIONAL ISO
STANDARD 14306
Second edition
2017-11
Industrial automation systems
and integration — JT file format
specification for 3D visualization
Systèmes d'automatisation industrielle et intégration — Spécification
de format de fichier JT pour visualisation 3D
Reference number
©
ISO 2017
© ISO 2017, Published in Switzerland
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ii © ISO 2017 – All rights reserved

Content
Content . iii
Foreword . xvi
Introduction . xvii
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and abbreviated terms . 1
3.1 Terms and definitions . 1
3.2 Abbreviated terms . 5
4 Notational conventions . 6
5 File Format . 14
5.1 File Structure . 14
5.1.1 File Header . 14
5.1.2 TOC Segment . 16
5.1.3 Data Segment . 17
5.2 Data Segments . 22
6 LSG Segment . 24
6.1 Graph Elements . 24
6.1.1 Node Elements . 25
6.1.2 Attribute Elements . 48
6.2 Property Atom Elements. 92
6.2.1 Base Property Atom Element . 92
6.2.2 String Property Atom Element . 93
6.2.3 Integer Property Atom Element . 94
6.2.4 Floating Point Property Atom Element . 94
6.2.5 JT Object Reference Property Atom Element. 95
6.2.6 Date Property Atom Element . 96
6.2.7 Late Loaded Property Atom Element . 97
6.2.8 Vector4f Property Atom Element . 99
6.3 Property Table . 99
6.3.1 Element Property Table . 100
7 Shape LOD Segment . 102
7.1 Shape LOD Element . 102
7.1.1 Base Shape LOD Element. 102
7.1.2 Vertex Shape LOD Element . 103
7.1.3 Tri-Strip Set Shape LOD Element . 118
7.1.4 Polyline Set Shape LOD Element . 118
7.1.5 Point Set Shape LOD Element . 119
7.1.6 Null Shape LOD Element . 120
7.2 Primitive Set Shape Element . 120
7.2.1 Lossless Compressed Primitive Set Data . 122
7.2.2 Lossy Quantized Primitive Set Data . 124
8 Geometry Segments . 129
8.1 STEP B-Rep Segment . 129
8.2 XT B-Rep Segment . 129
8.3 JT ULP Segment . 129
8.4 JT LWPA Segment . 129
8.5 Wireframe Segment . 129
8.6 JT B-Rep Element (deprecated) . 129
9 Meta Data Segment . 131
9.1 Property Proxy Meta Data Element . 131
9.1.1 Date Property Value . 133
9.2 PMI Manager Meta Data Element . 134
9.2.1 PMI Entities . 137
9.2.2 PMI Associations . 158
9.2.3 PMI User Attributes . 160
9.2.4 PMI String Table . 161
9.2.5 PMI Model Views . 161
9.2.6 Generic PMI Entities . 163
9.2.7 PMI CAD Tag Data . 169
9.2.8 PMI Polygon Data . 170
10 Data Compression and Encoding . 174
10.1 Common Compression Data Collection Formats . 174
10.1.1 Int32 Compressed Data Packet . 174
10.1.2 Int32 Compressed Data Packet Mk. 2 . 179
10.1.3 Float64 Compressed Data Packet . 185
10.1.4 Compressed Vertex Coordinate Array . 189
10.1.5 Compressed Vertex Normal Array . 190
10.1.6 Compressed Vertex Texture Coordinate Array . 192
10.1.7 Compressed Vertex Colour Array . 194
10.1.8 Compressed Vertex Flag Array . 196
10.1.9 Point Quantizer Data . 197
10.1.10 Texture Quantizer Data . 197
10.1.11 Colour Quantizer Data . 198
10.1.12 Uniform Quantizer Data . 200
10.1.13 Compressed Entity List for Non-Trivial Knot Vector . 200
10.1.14 Compressed Control Point Weights Data . 204
10.1.15 Compressed Curve Data . 205
10.1.16 Compressed CAD Tag Data . 208
10.2 Encoding Algorithms . 211
10.2.1 Uniform Data Quantization . 211
10.2.2 Bitlength CODEC . 211
10.2.3 Arithmetic CODEC . 212
10.2.4 Deering Normal CODEC . 217
10.3 zlib compression . 219
11 Common Data Conventions and Constructs . 220
11.1 Late-Loading Data . 220
11.2 TOC Segment Location . 220
11.3 Bit Fields. 220
11.4 Empty Field . 220
11.5 Local version numbers . 220
11.5.1 Version numbers . 221
11.6 Hash Value . 223
11.7 Scene graph construction . 223
11.8 Metadata Conventions . 224
11.8.1 CAD Properties . 224
11.8.2 PMI Properties . 228
11.8.3 Tessellation Properties . 324
11.8.4 Miscellaneous Properties . 325
11.9 LSG Attribute Accumulation Semantics . 326
11.10 LSG Part Structure . 327
11.11 Range LOD Node Alternative Rep Selection . 327
11.12 Brep Face Group Associations . 327
11.13 Handling of different states / variants in a JT file . 328
11.13.1 Reference Sets . 329
11.14 Watermarks . 329
11.14.1 Background . 329
11.14.2 Issue – Missing specification in the ISO . 330
iv © ISO 2017– All rights reserved

11.14.3 Recommended Solution . 330
11.14.4 Issue – Protection of data . 332
12 Conformance requirements. 333
Annex A (informative) Object Type Identifiers . 334
Annex B (normative) STEP B-Rep . 338
B.1 STEP B-Rep Element . 338
B.1.1 STEP B-Rep Data . 338
B.1.2 STEP schema . 339
B.1.3 STEP format . 339
B.1.4 STEP external element reference in ISO 10303-21 . 339
Annex C (normative) STEP schema . 341
Annex D (informative) Coding Algorithms – An Implementation . 414
D.1 Common classes . 414
D.1.1 CntxEntry class . 414
D.1.2 CntxEntryBase2 class . 414
D.1.3 ProbabilityContext class. 415
D.1.4 ProbContex2 class . 416
D.1.5 CodecDriver class . 419
D.1.6 CodecDriver2 class . 422
D.2 Bitlength decoding classes . 426
D.2.1 BitLengthCodec class . 426
D.2.2 BitLengthCodec2 class . 430
D.3 Arithmetic decoding classes . 438
D.3.1 ArithmeticProbabilityRange class . 438
D.3.2 ArithmeticCodec class . 438
D.3.3 ArithmeticCodec2 class . 442
D.4 Deering Normal decoding classes . 446
D.4.1 DeeringNormalLookupTable class . 446
D.4.2 DeeringNormalCodec class . 448
Annex E (informative) Hashing – An Implementation . 451
Annex F (informative) Polygon Mesh Topology Coder . 454
F.1 DualVFMesh . 455
F.2 Topology Decoder . 461
F.2.1 MeshCoderDriver class . 461
F.2.2 MeshCodec class . 464
F.2.3 MeshDecoder class . 470
Annex G (informative)  XT B- Rep segment . 473
G.1 XT B-Rep Element . 473
G.1.1 XT B-Rep Data . 474
G.2 Procedural Geometry . 474
G.2.1 Background . 474
G.2.2 Issue . 474
G.2.3 Recommended Solution . 476
G.3 Non-Manifold Bodies . 476
G.3.1 Background . 476
G.3.2 Issue . 477
G.3.3 Recommended Solution . 477
Annex H (informative)  XT B- Rep data segment. 478
H.1 Introduction to the XT B- Rep data segment . 478
H.2 Logical Layout . 478
H.2.1 Schema . 479
H.2.2 Embedded schemas . 479
H.2.3 Field types . 480
H.2.4 Variable-length nodes . 481
H.2.5 Unresolved indices . 481
H.3 Physical Layout . 481
H.3.1 Binary . 481
H.4 Model Structure . 482
H.4.1 Topology. 482
H.4.2 General points . 483
H.4.3 Entity definitions . 483
H.4.4 Entity matrix . 487
H.4.5 Representation of manifold bodies . 487
H.5 Schema Definition . 489
H.5.1 Underlying types . 489
H.5.2 Geometry . 489
H.5.3 Topology. 521
H.5.4 Associated Data . 534
H.6 Node Types . 545
H.7 Node Classes . 547
H.8 System Attribute Definitions . 547
H.8.1 Hatching Attributes . 547
H.8.2 Density Attributes . 549
H.8.3 Region . 551
H.8.4 Colour . 551
H.8.5 Reflectivity . 551
H.8.6 Translucency . 552
H.8.7 Name . 552
H.8.8 Incremental faceting . 552
H.8.9 Transparency . 552
H.8.10 Non-mergeable edges . 553
H.8.11 Group merge behaviour . 553
H.8.12 Unicode name . 553
H.8.13 Monikers . 553
Annex I (informative) PMI Data Segment . 559
Annex J (informative) Mapping table from ISO 10303-42 to XT B-Rep . 560
J.1 Wireframe Geometry . 560
J.2 Surfaces without topology . 560
J.3 Shapes represented by wireframe models with topology . 561
J.4 Manifold Surfaces with Topology . 561
J.5 Advanced boundary representation solids . 563
J.5.1 Color . 564
J.5.2 Name . 565
J.5.3 Wireframe style . 565
J.5.4 Visibility . 566
Annex K (informative) JT B-rep Segment . 567
K.1 JT B-Rep Element . 567
K.1.1 Topological Entity Counts . 569
K.1.2 Geometric Entity Counts . 570
K.1.3 Topology Data . 571
K.1.4 Geometric Data . 580
K.1.5 Topological Entity Tag Counters . 589
K.1.6 B-Rep CAD Tag Data . 591
Annex L (informative) Wireframe Segment . 592
L.1 Wireframe Rep Element . 592
L.1.1 Wireframe MCS Curves Geometric Data . 594
L.1.2 Wireframe Rep CAD Tag Data . 594
Annex M (informative) JT ULP Segment . 596
M.1 JT ULP Element . 596
M.1.1 Topology Data . 598
M.1.2 Geometric Data . 615
M.1.3 Material Attribute Element Properties . 637
vi © ISO 2017– All rights reserved

M.1.4 Information Recovery . 638
M.1.5 Non-Manifold Bodies . 643
M.2 JT LWPA Segment . 643
M.2.1 JT LWPA Element . 644
M.2.2 Analytic Surface Geometry. 644
Annex N (informative) Change History . 647
N.1 General . 647
N.2 Changes made in edition 2 . 647
N.2.1 Summary of the changes . 647
N.2.2 Additions made to the document . 647
N.2.3 Addition of a new STEP B-rep segment definition . 647
N.2.4 Updates of the documentation from the Prostep industrialization quidelines . 648
N.2.5 Addition of a conformance clause. . 648
N.2.6 Addition of a mapping table JT ISO to STEP. . 648
N.2.7 Content modified from edition 1 . 648
N.2.8 Elements deprecated from edition 1 . 648
Bibliography . 649

Figures
Figure 1 — rectangle box diagram .6
Figure 2 — folder diagram .6
Figure 3 — rectangle box with lines at left and right sides diagram .7
Figure 4 — rectangle box with clipped right side corners .7
Figure 5 — compressed data packet diagram .7
Figure 6 — data type : field name diagram .8
Figure 7 — data filed dependency example .9
Figure 8 — loop construct example . 10
Figure 9 — loop construct with iterations example . 10
Figure 10 — JT File Structure . 14
Figure 11 — File Header data collection . 15
Figure 12 — TOC Segment data collection . 16
Figure 13 — TOC Entry data collection . 17
Figure 14 — Data Segment data collection . 18
Figure 15 — Segment Header data collection . 18
Figure 16 — Data collection . 20
Figure 17 — Logical Element Header data collection . 20
Figure 18 — Element Header data collection . 20
Figure 19 — Logical Element Header ZLIB data collection . 22
Figure 20 — LSG Segment data collection . 24
Figure 21 — Base Node Element data collection . 25
Figure 22 — Base Node Data collection . 25
Figure 23 — Partition Node Element data collection . 27
Figure 24 — Vertex Count Range data collection . 28
Figure 25 — Group Node Element data collection . 29
Figure 26 — Group Node Data collection . 30
Figure 27 — Instance Node Element data collection . 31
Figure 28 — Part Node Element data collection. 32
Figure 29 — Assembly node with SUBNODE . 32
Figure 30 — Assembly node without SUBNODE . 33
Figure 31 — Displaying Nodes that have SUBNODE properties . 33
Figure 32 — Meta Data Node Element data collection . 34
Figure 33 — Meta Data Node Data collection . 34
Figure 34 — LOD Node Element data collection . 34
Figure 35 — LOD Node Data collection . 35
Figure 36 — Range LOD Node Element data collection . 36
Figure 37 — Switch Node Element data collection . 37
Figure 38 — Base Shape Node Element data collection . 38
Figure 39 — Base Shape Data collection . 38
Figure 40 —Vertex Count Range data collection . 40
Figure 41 — Vertex Shape Node Element data collection . 41
Figure 42 — Vertex Shape Data collection . 41
Figure 43 — Quantization Parameters data collection . 42
Figure 44 — Tri-Strip Set Shape Node Element data collection . 42
Figure 45 — Polyline Set Shape Node Element data collection . 43
Figure 46 — Point Set Shape Node Element data collection . 44
Figure 47 — Polygon Set Shape Node Element data collection . 45
Figure 48 — NULL Shape Node Element data collection . 45
Figure 49 — Primitive Set Shape Node Element data collection . 46
Figure 50 — Primitive Set Quantization Parameters data collection . 48
Figure 51 — Base Attribute Data collection . 49
Figure 52 — Material Attribute Element data collection . 51
Figure 53 — Texture Image Attribute Element data collection . 54
Figure 54 — Texture Vers-1 Data collection . 56
Figure 55 — Texture Environment data collection. 58
Figure 56 — Texture Coord Generation Parameters data collection . 61
Figure 57 — Inline Texture Image Data collection . 62
Figure 58 — Image Format Description data collection . 63
Figure 59 — Texture Vers-2 Data collection . 66
Figure 60 — Texture Vers-3 Data collection . 69
Figure 61 — Draw Style Attribute Element data collection . 72
Figure 62 — Light Set Attribute Element data collection . 73
Figure 63 — Infinite Light Attribute Element data collection . 74
Figure 64 — Base Light Data collection . 75
Figure 65 — Shadow Parameters data collection . 76
Figure 66 — Point Light Attribute ElementPoint Light Attribute Element data collection . 78
Figure 67 — Spread Angle value with respect to the light cone . 79
Figure 68 — Attenuation Coefficients data collection . 80
Figure 69 — Linestyle Attribute Element data collection . 81
Figure 70 — Pointstyle Attribute Element data collection . 82
Figure 71 — Geometric Transform Attribute Element data collection . 83
Figure 72 — Shader Effects Attribute Element data collection . 85
Figure 73 — Texture Coordinate Generator Attribute Element data collection . 87
Figure 74 — Mapping Plane Element data collection . 88
Figure 75 — Mapping Cylinder Element data collection . 89
Figure 76 — Mapping Sphere Element data collection . 90
Figure 77 — Mapping TriPlanar Element data collection . 91
Figure 78 — Base Property Atom Element data collection . 92
Figure 79 — Base Property Atom Data collection. 93
Figure 80 — String Property Atom Element data collection . 93
Figure 81 — Integer Property Atom Element data collection . 94
Figure 82 — Floating Point Property Atom Element data collection . 95
Figure 83 — JT Object Reference Property Atom Element data collection . 95
Figure 84 — Date Property Atom Element data collection . 96
Figure 85 — Late Loaded Property Atom Element data collection . 98
Figure 86 — Vector4f Property Atom Element data collection . 99
Figure 87 — Property Table data collection . 100
Figure 88 — Element Property Table data collection . 101
Figure 89 — Shape LOD Segment data collection . 102
Figure 90 — Base Shape LOD Element data collection . 102
Figure 91 — Base Shape LOD Data collection . 103
Figure 92 — Vertex Shape LOD Element data collection . 103
Figure 93 — Vertex Shape LOD Data collection . 104
Figure 94 — TopoMesh LOD Data collection . 106
Figure 95 — TopoMesh LOD Data collection . 106
Figure 96 — TopoMesh Topologically Compressed LOD Data collection . 107
viii © ISO 2017– All rights reserved

Figure 97 — Topologically Compressed Rep Data Collection . 108
Figure 98 — Topologically Compressed Vertex Records data collection . 111
Figure 99 — TopoMesh Compressed Rep Data V1 data collection. 112
Figure 100 — TopoMesh Compressed Rep Data V2 data collection. 115
Figure 101 — Tri-Strip Set Shape LOD Element data collection . 118
Figure 102 — Polyline Set Shape LOD Element data collection . 119
Figure 103 — Point Set Shape LOD Element data collection
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