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Part 1:  Functional specification

6 DRM classes

6.1 Introduction

6.1.1 Table of contents

Table 6.1 is the table of contents for this clause.

Table 6.1 — Table of contents

6 DRM classes

6.1 Introduction

6.1.1 Table of contents

6.1.2 Description

6.2 Constraints

6.2.1 Overview

6.2.2 Axis type constraints

6.2.3 Colour mapping constraints

6.2.4 Colour table size

6.2.5 Connected edge constraints

6.2.6 Contained node constraints

6.2.7 Continuous LOD constraints

6.2.8 Corresponding same data type

6.2.9 Cylindrical structure

6.2.10 Distinct link objects

6.2.11 Edges bordering faces

6.2.12 Environment_Root spatial reference frame

6.2.13 Face_Direction levels 0 - 3

6.2.14 Feature_Edge constraints

6.2.15 Face ring edge consistency

6.2.16 Hierarchy summary constraints

6.2.17 Homogeneous light rendering properties

6.2.18 Image_Anchor spatial reference frame

6.2.19 Image mapping functions and texture coordinates

6.2.20 Index_Codes within tables

6.2.21 Inheritance rule for Location

6.2.22 Level of detail related organizing principle

6.2.23 LSR model and reference surfaces

6.2.24 LSR_Transformation components

6.2.25 Mandatory metadata

6.2.26 Model reference type constraints

6.2.27 Model spatial reference frame

6.2.28 Nested primitive geometry

6.2.29 Non-crossing aggregations

6.2.30 Non-crossing associations

6.2.31 Non-cyclic aggregations

6.2.32 Non-empty Environment_Root

6.2.33 Non-empty Model

6.2.34 Non-overlapping DRM class summary items

6.2.35 Non-selfoverlapping Perimeter_Data locations

6.2.36No property conflicts

6.2.37 Octant related organizing principle

6.2.38 Perimeter_Related_Feature_Topology partitioning

6.2.39 Perimeter related organizing principle

6.2.40 Precedence of DRM_Property_Set_Index

6.2.41 Primitive_Summary_Item constraints

6.2.42 Property_Characteristic constraints

6.2.43 Property meaning constraints

6.2.44 Property set components

6.2.45 Property set table size

6.2.46 Publishable object

6.2.47 Quadrant related organizing principle

6.2.48 Reference to Data_Table_Library

6.2.49 Relative spatial axes values

6.2.50 Required reference vector location

6.2.51 Separating plane organizing principle

6.2.52 Spatial index related organizing principle

6.2.53 State related organizing principle

6.2.54 Time dependency

6.2.55 Time interval calculation

6.2.56 Variable meaning constraints

6.3.DRM class specifications

6.3.1 Overview

6.3.2 DRM_Absolute_Time

6.3.3 DRM_Absolute_Time_Interval

6.3.4 DRM_Access

6.3.5 DRM_Aggregate_Feature

6.3.6 DRM_Aggregate_Geometry

6.3.7 DRM_Alternate_Hierarchy_Related_Features

6.3.8 DRM_Alternate_Hierarchy_Related_Geometry

6.3.9 DRM_Ambient_Colour

6.3.10 DRM_Animation_Behaviour

6.3.11 DRM_Animation_Related_Geometry

6.3.12 DRM_Arc

6.3.13 DRM_Areal_Feature

6.3.14 DRM_Attachment_Point

6.3.15 DRM_Axis

6.3.16 DRM_AZ_2D_Location

6.3.17 DRM_Base Association_Data

6.3.18 DRM_Base_LOD_Data

6.3.19 DRM_Base_Positional_Light

6.3.20 DRM_Base_Spatial_Association_Data

6.3.21 DRM_Base_Summary_Item

6.3.22 DRM_Base_Time_Data

6.3.23 DRM_Blend_Directional_Light

6.3.24 DRM_Bounding_Volume

6.3.25 DRM_Browse_Media

6.3.26 DRM_Camera_Point

6.3.27 DRM_CC_3D_Location

6.3.28 DRM_CD_3D_Location

6.3.29 DRM_CD_Surface_Location

6.3.30 DRM_Citation

6.3.31 DRM_Classification_Data

6.3.32 DRM_Classification_Related_Features

6.3.33 DRM_Classification_Related_Geometry

6.3.34 DRM_CM_3D_Location

6.3.35 DRM_CMY_Colour

6.3.36 DRM_CMY_Colour_Control_Link

6.3.37 DRM_Collision_Volume

6.3.38 DRM_Colour

6.3.39 DRM_Colour_Data

6.3.40 DRM_Colour_Index

6.3.41 DRM_Colour_Index_Control_Link

6.3.42 DRM_Colour_Shininess

6.3.43 DRM_Colour_Table

6.3.44 DRM_Colour_Table_Group

6.3.45 DRM_Colour_Table_Library

6.3.46 DRM_Cone_Directional_Light

6.3.47 DRM_Conformal_Behaviour

6.3.48 DRM_Contact_Point

6.3.49 DRM_Continuous_LOD_Related_Geometry

6.3.50 DRM_Control_Link

6.3.51 DRM_Cross_Reference

6.3.52 DRM_Cylindrical_Volume_Extent

6.3.53 DRM_Data_Quality

6.3.54 DRM_Data_Table

6.3.55 DRM_Data_Table_Library

6.3.56 DRM_Description

6.3.57 DRM_Diffuse_Colour

6.3.58 DRM_Directional_Light_Behaviour

6.3.59 DRM_Distance_LOD_Data

6.3.60 DRM_DRM_Class_Summary_Item

6.3.61 DRM_EC_Augmented_3D_Location

6.3.62 DRM_EC_Surface_Location

6.3.63 DRM_EDCS_Use_Summary_Item

6.3.64 DRM_Edge_Direction

6.3.65 DRM_EI_3D_Location

6.3.66 DRM_Ellipse

6.3.67 DRM_Emissive_Colour

6.3.68 DRM_Enumeration_Axis

6.3.69 DRM_Environment_Root

6.3.70 DRM_Environmental_Domain_Summary

6.3.71 DRM_Expression

6.3.72 DRM_Face_Direction

6.3.73 DRM_Fade_Range

6.3.74 DRM_Feature_Edge

6.3.75 DRM_Feature_Face

6.3.76 DRM_Feature_Face_Ring

6.3.77 DRM_Feature_Hierarchy

6.3.78 DRM_Feature_Model

6.3.79 DRM_Feature_Model_Instance

6.3.80 DRM_Feature_Node

6.3.81 DRM Feature Representation

6.3.82 DRM_Feature_Topology

6.3.83 DRM_Feature_Topology_Hierarchy

6.3.84 DRM_Feature_Volume

6.3.85 DRM_Feature_Volume_Shell

6.3.86 DRM_Finite_Element_Mesh

6.3.87 DRM_Flashing_Light_Behaviour

6.3.88 DRM_Function

6.3.89 DRM_Functional_Association_Data

6.3.90 DRM_Geometric_Centre

6.3.91 DRM_Geometry_Edge

6.3.92 DRM_Geometry_Face

6.3.93 DRM_Geometry_Hierarchy

6.3.94 DRM_Geometry_Model

6.3.95 DRM_Geometry_Model_Instance

6.3.96 DRM_Geometry_Node

6.3.97 DRM_Geometry_Representation

6.3.98 DRM_Geometry_Topology

6.3.99 DRM_Geometry_Topology_Hierarchy

6.3.100 DRM_Geometry_Volume

6.3.101 DRM_Grid_Overlap

6.3.102 DRM_HAEC_3D_Location

6.3.103 DRM_HEEC_3D_Location

6.3.104 DRM_HEEQ_3D_Location

6.3.105 DRM_Hierarchy_Data

6.3.106 DRM_Hierarchy_Summary_Item

6.3.107 DRM_HSV_Colour

6.3.108 DRM_HSV_Colour_Control_Link

6.3.109 DRM_Icon

6.3.110 DRM_Image

6.3.111 DRM_Image_Anchor

6.3.112 DRM_Image_Library

6.3.113 DRM_Image_Lookup

6.3.114 DRM_Image_Mapping_Function

6.3.115 DRM_In_Out

6.3.116 DRM_Index_LOD_Data

6.3.117 DRM_Infinite_Light

6.3.118 DRM_Inline_Colour

6.3.119 DRM_Interface_Template

6.3.120 DRM_Interval_Axis

6.3.121 DRM_Irregular_Axis

6.3.122 DRM_Keywords

6.3.123 DRM_Label

6.3.124 DRM_LCC_Augmented_3D_Location

6.3.125 DRM_LCC_Surface_Location

6.3.126 DRM_Library

6.3.127 DRM_Light_Rendering_Behaviour

6.3.128 DRM_Light_Rendering_Properties

6.3.129 DRM_Light_Rendering_Properties_Control_Link

6.3.130 DRM_Light_Source

6.3.131 DRM_Light_Source_Control_Link

6.3.132 DRM_Line

6.3.133 DRM_Lineage

6.3.134 DRM_Linear_Feature

6.3.135 DRM_Linear_Geometry

6.3.136 DRM_Literal

6.3.137 DRM_Lobe_Data

6.3.138 DRM_Local_4x4

6.3.139 DRM_Location

6.3.140 DRM_Location_2D

6.3.141 DRM_Location_3D

6.3.142 DRM_Location_Surface

6.3.143 DRM_LOD_Related_Features

6.3.144 DRM_LOD_Related_Geometry

6.3.145 DRM_LSR_2D_Location

6.3.146 DRM_LSR_3D_Location

6.3.147 DRM_LSR_3D_Location_Control_Link

6.3.148 DRM_LSR_Transformation

6.3.149 DRM_LSR_Transformation_Step

6.3.150 DRM_LTSAS_3D_Location

6.3.151 DRM_LTSAS_Surface_Location

6.3.152 DRM_LTSC_3D_Location

6.3.153 DRM_LTSC_Surface_Location

6.3.154 DRM_LTSE_3D_Location

6.3.155 DRM_LTSE_Surface_Location

6.3.156 DRM_M_Augmented_3D_Location

6.3.157 DRM_M_Surface_Location

6.3.158 DRM_Map_Scale_LOD_Data

6.3.159 DRM_Mesh_Face_Table

6.3.160 DRM_Model

6.3.161 DRM_Model_Instance_Template_Index

6.3.162 DRM_Model_Library

6.3.163 DRM_Moving_Light_Behaviour

6.3.164 DRM_Octant_Data

6.3.165 DRM_Octant_Related_Features

6.3.166 DRM_Octant_Related_Geometry

6.3.167 DRM_OM_Augmented_3D_Location

6.3.168 DRM_OM_Surface_Location

6.3.169 DRM_Overload_Priority_Index

6.3.170 DRM_Parallelepiped_Volume_Extent

6.3.171 DRM_Perimeter_Data

6.3.172 DRM_Perimeter_Related_Feature_Topology

6.3.173 DRM_Perimeter_Related_Features

6.3.174 DRM_Perimeter_Related_Geometry

6.3.175 DRM_Perimeter_Related_Geometry_Topology

6.3.176 DRM_Point

6.3.177 DRM_Point_Feature

6.3.178 DRM_Polar_2D_Location

6.3.179 DRM_Polygon

6.3.180 DRM_Polygon_Control_Link

6.3.181 DRM_Polyhedron

6.3.182 DRM_Positional_Light

6.3.183 DRM_Predefined_Function

6.3.184 DRM_Presentation_Domain

6.3.185 DRM_Primitive_Colour

6.3.186 DRM_Primitive_Feature

6.3.187 DRM_Primitive_Geometry

6.3.188 DRM_Primitive_Summary_Item

6.3.189 DRM_Process_Step

6.3.190 DRM_Property

6.3.191 DRM_Property_Characteristic

6.3.192 DRM_Property_Description

6.3.193 DRM_Property_Grid

6.3.194 DRM_Property_Grid_Hook_Point

6.3.195 DRM_Property_Set

6.3.196 DRM_Property_Set_Index

6.3.197 DRM_Property_Set_Index_Control_Link

6.3.198 DRM_Property_Set_Table

6.3.199 DRM_Property_Set_Table_Group

6.3.200 DRM_Property_Set_Table_Library

6.3.201 DRM_Property_Table

6.3.202 DRM_Property_Table_Reference

6.3.203 DRM_Property_Table_Reference_Control_Link

6.3.204 DRM_Property_Value

6.3.205 DRM_Proximity_Data

6.3.206 DRM_PS_Augmented_3D_Location

6.3.207 DRM_PS_Surface_Location

6.3.208 DRM_Pseudo_Code_Function

6.3.209 DRM_Pyramid_Directional_Light

6.3.210 DRM_Quadrant_Data

6.3.211 DRM_Quadrant_Related_Features

6.3.212 DRM_Quadrant_Related_Geometry

6.3.213 DRM_Reference_Origin

6.3.214 DRM_Reference_Surface

6.3.215 DRM_Reference_Vector

6.3.216 DRM_Reference_Vector_Control_Link

6.3.217 DRM_Regular_Axis

6.3.218 DRM_Relative_Time

6.3.219 DRM_Relative_Time_Interval

6.3.220 DRM_Rendering_Priority_Level

6.3.221 DRM_Rendering_Properties

6.3.222 DRM Responsible_Party

6.3.223 DRM_RGB_Colour

6.3.224 DRM_RGB_Colour_Control_Link

6.3.225 DRM_Rotating_Light_Behaviour

6.3.226 DRM_Rotation

6.3.227 DRM_Rotation_Control_Link

6.3.228 DRM_Scale

6.3.229 DRM_Scale_Control_Link

6.3.230 DRM_Season

6.3.231 DRM_SEC_3D_Location

6.3.232 DRM_SEDRIS_Abstract_Base

6.3.233 DRM_Separating_Plane

6.3.234 DRM_Separating_Plane_Data

6.3.235 DRM_Separating_Plane_Related_Geometry

6.3.236 DRM_Separating_Plane_Relations

6.3.237 DRM_SEQ_3D_Location

6.3.238 DRM_SM_3D_Location

6.3.239 DRM_SMS_3D_Location

6.3.240 DRM_Sound

6.3.241 DRM_Sound_Instance

6.3.242 DRM_Sound_Instance_Control_Link

6.3.243 DRM_Sound_Library

6.3.244 DRM_Sound_Volume

6.3.245 DRM_Source

6.3.246 DRM_Spatial_Association_Data

6.3.247 DRM_Spatial_Extent

6.3.248 DRM_Spatial_Index_Data

6.3.249 DRM_Spatial_Index_Related_Feature_Topology

6.3.250 DRM_Spatial_Index_Related_Features

6.3.251 DRM_Spatial_Index_Related_Geometry

6.3.252 DRM_Spatial_Index_Related_Geometry_Topology

6.3.253 DRM_Spatial_Resolution_LOD_Data

6.3.254 DRM_Specular_Colour

6.3.255 DRM_Spherical_Volume_Extent

6.3.256 DRM_Spot_Light

6.3.257 DRM_SRF_Summary

6.3.258 DRM_Stamp_Behaviour

6.3.259 DRM_State_Control_Link

6.3.260 DRM_State_Data

6.3.261 DRM_State_Related_Features

6.3.262 DRM_State_Related_Geometry

6.3.263 DRM_Strobing_Light_Behaviour

6.3.264 DRM_Surface_Geometry

6.3.265 DRM_Symbol

6.3.266 DRM_Symbol_Library

6.3.267 DRM_Table_Property_Description

6.3.268 DRM_Tack_Point

6.3.269 DRM_Text

6.3.270 DRM_Texture_Coordinate

6.3.271 DRM_Texture_Coordinate_Control_Link

6.3.272 DRM_Time_Constraints_Data

6.3.273 DRM_Time_Interval

6.3.274 DRM_Time_Of_Day

6.3.275 DRM_Time_Point

6.3.276 DRM_Time_Related_Features

6.3.277 DRM_Time_Related_Geometry

6.3.278 DRM_TM_Augmented_3D_Location

6.3.279 DRM_TM_Surface_Location

6.3.280 DRM_Transformation

6.3.281 DRM_Translation

6.3.282 DRM_Translation_Control_Link

6.3.283 DRM_Translucency

6.3.284 DRM_Translucency_Control_Link

6.3.285 DRM_Transmittal_Root

6.3.286 DRM_Transmittal_Summary

6.3.287 DRM_Twinkling_Light_Behaviour

6.3.288 DRM_Union_Of_Feature_Topology

6.3.289 DRM_Union_Of_Features

6.3.290 DRM_Union_Of_Geometry

6.3.291 DRM_Union_Of_Geometry_Hierarchy

6.3.292 DRM_Union_Of_Geometry_Topology

6.3.293 DRM_Union_Of_Primitive_Geometry

6.3.294 DRM_Variable

6.3.295 DRM_Vertex

6.3.296 DRM_Volume

6.3.297 DRM_Volume_Extent

6.3.298 DRM_Volume_Geometry

6.3.299 DRM_Volume_Light_Behaviour

6.3.300 DRM_Volume_LOD_Data

6.3.301 DRM_Volume_Object

6.3.302 DRM_Volumetric_Feature

6.3.303 DRM_World_3x3

6.3.304 DRM_World_Transformation

6.1.2 Description

This clause specifies the DRM classes used within this part of ISO/IEC 18023 to specify the various objects that are to be represented. Such DRM classes are composed of both fundamental data types and references to other DRM classes using the handle data types specified in 5.4.3 Object. These are used as the building blocks for more complex data structures that describe composites of information.

6.2 Constraints

6.2.1 Overview

The constraints stated below specify the restrictions on field values and associations that may apply when creating and modifying DRM class instances. Since many of these constraints apply to multiple DRM classes, they are specified here and only referenced in 6.3 DRM class specifications.

6.2.2 Axis type constraints

The following constraints apply:

  1. In a <DRM Enumeration Axis> instance X,
    1. The axis_type of X shall correspond to an EA T bound to the abstract value type ENUMERATION.
    2. The entries of X's axis_value_array shall be distinct, valid EEs for T.
  2. In a <DRM Interval Axis> instance X,
    1. The axis_type shall correspond to an EA bound to a numeric value type.
    2. Each individual entry in X's axis_interval_value_array shall have a value_type consistent with the numeric data type to which the axis_type's value is bound, and this value_type shall be the same for all entries in the axis_interval_value_array.
    3. If the axis_type is bound to an EQ, the value_unit shall be a member of the specified EQ.
    4. If the axis_type is not bound to an EQ, the value_unit and scale_unit shall be set to EUC_UNITLESS and ESC_UNI, respectively.
    5. All entries in X's axis_interval_value_array shall be mutually disjoint.
    6. The entries in X's axis_interval_value_array shall be arranged in either monotonically ascending or monotonically descending order.
  3. In a <DRM Irregular Axis> instance X,
    1. The axis_type shall correspond to an EA bound to a numeric value type.
    2. Each individual entry in X's axis_value_array shall have a value_type consistent with the numeric data type to which the axis_type's value is bound, and this value_type shall be the same for all entries in the axis_value_array.
    3. If the axis_type is bound to an EQ, the value_unit shall be a member of the specified EQ.
    4. If the axis_type is not bound to an EQ, the value_unit and scale_unit shall be set to EUC_UNITLESS and ESC_UNI, respectively.
    5. All entries in X's axis_value_array shall be distinct, and
    6. The entries in X's axis_value_array shall be arranged in either monotonically ascending or monotonically descending order.
  4. In a <DRM Regular Axis> instance X,
    1. The axis_type shall correspond to an EA bound to a numeric value type.
    2. The value_type of the first_value and spacing field values shall be the same, and shall be consistent with the numeric data type to which the axis_type's value is bound.
    3. If the axis_type is bound to an EQ, the value_unit shall be a member of the specified EQ.
    4. If the axis_type is not bound to an EQ, the value_unit and scale_unit shall be set to EUC_UNITLESS and ESC_UNI, respectively.
  5. In regard to spatial <DRM Axis> instances,
    1. A spatial <DRM Axis> is a <DRM Axis> instance with one of the following as its axis_type.
      1. For angular coordinates, such as latitude and longitude, EAC_SPATIAL_ANGULAR_PRIMARY_COORDINATE and
        EAC_SPATIAL_ANGULAR_SECONDARY_COORDINATE        ;
      2. For x, y coordinates,
        EAC_SPATIAL_LINEAR_PRIMARY_COORDINATE and
        EAC_SPATIAL_LINEAR_SECONDARY_COORDINATE        ; and
      3. For z and elevation coordinates,
        EAC_SPATIAL_LINEAR_TERTIARY_COORDINATE.
    2. The first spatial_axes_count <DRM Axis> components of a <DRM Property Grid> instance shall be spatial <DRM Axis> instances, each of which uniquely corresponds to a coordinate of the <DRM Property Grid> instance's spatial reference frame.
    3. No other <DRM Axis> instances in any other context shall be spatial.

6.2.3 Colour mapping constraints

The colour_mapping field of a <DRM Colour> shall not be empty.

In addition,

  1. The colour_mapping field of a <DRM Colour> shall not be empty.
  2. The PRIMARY and SECONDARY flags may only be used for objects with <DRM Light Rendering Properties>.
  3. The PRIMARY flag may not be combined with any other use of the Colour_Mapping data type.
  4. The SECONDARY flag may not be combined with any other use of the Colour_Mapping data type.

6.2.4 Colour table size

For a given <DRM Colour Table Group> instance G with table_size = k, each <DRM Colour Table> component T of G shall have k <DRM Primitive Colour> components. <DRM Colour Table> components of a <DRM Colour Table Group> are free to have different types of <DRM Primitive Colour> components from other <DRM Colour Table> components.

EXAMPLE Some components use <DRM Specular Colour>; some do not.

6.2.5 Connected edge constraints

The following constraints apply to instances of connected edge DRM classes:

  1. A <DRM Feature Node> N has the following relationship with its <DRM Feature Edge> components, if any exist.
    1. For each <Feature Edge> that has N as a starting node, N shall be associated to that <DRM Feature Edge>.
    2. For each <Feature Edge> that has N as an ending node, N shall be associated to that <DRM Feature Edge>.
    3. If N is neither the starting node nor the ending node of a given <DRM Feature Edge>, N shall be associated to that <DRM Feature Edge>.
    4. Consequently, for any given <DRM Feature Edge> E of which N is a starting or ending node, E shall appear among the associates of N either:
      1. once, if N is E’s starting node and not its ending node,
      2. once, if N is E’s ending node and not its starting node, or
      3. twice, if E is a loop.
  2. A <DRM Geometry Node> N has the following relationship with its associated <DRM Geometry Edge> instances, if any exist.
    1. For each <DRM Geometry Edge> that has N as a starting node, N shall be associated to that <DRM Geometry Edge>.
    2. For each <DRM Geometry Edge> that has N as an ending node, N shall be associated to that <DRM Geometry Edge>.
    3. If N is neither the starting node nor the ending node of a given <DRM Geometry Edge>, N shall not be associated to that <Geometry Edge>.
    4. Consequently, for any given <DRM Geometry Edge> E of which N is a starting or ending node, E shall appear among the associates of N either:
      1. once, if N is E’s starting node and not its ending node,
      2. once, if N is E’s ending node and not its starting node, or
      3. twice, if E is a loop.

6.2.6 Contained node constraints

The following constraints apply to instances of contained node DRM classes:

  1. A <DRM Feature Face> instance F shall have the following relationship with its associated <DRM Feature Node> instances, if any exist. At any feature topology level, if F is associated with any <DRM Feature Node> instance N, N shall lie within the external ring of F, if any, and shall not lie within any of the internal rings of F, if any. Conversely, if a <DRM Feature Node> instance N lies within the boundaries of F, N shall be associated with F. If no <DRM Feature Node> instances lie within the boundaries of F, F shall not be associated with any <DRM Feature Node> instances.
  2. A <DRM Feature Volume> instance V shall have the following relationship with its associated <DRM Feature Node> instances, if any exist. At any feature topology level, if V is associated with any <DRM Feature Node> instance N, N shall lie completely within the external shell of V, if any, and shall not lie within any of the internal shells of V, if any. Conversely, if a <DRM Feature Node> instance N lies within the boundaries of V, N shall be associated with V. If no <DRM Feature Node> instances lie within the boundaries of V, V shall not be associated with any <DRM Feature Node> instances.
  3. A <DRM Geometry Face> instance F shall have the following relationship with its associated <DRM Geometry Node> instances, if any. At any geometry topology level, if E is associated with any <DRM Geometry Node> instances N, N shall lie within the interior of F. Conversely, if a <DRM Geometry Node> instance N lies within the interior of F, N shall be associated with F. If no <DRM Geometry Node> instances lie within the boundaries of F, F shall not be associated with any <DRM Geometry Node> instances.
  4. A <DRM Geometry Volume> instance V shall have the following relationship with its associated <DRM Geometry Node> instances, if any exist. At any geometry topology level, if V is associated with any <DRM Geometry Node> instance N, N shall lie within the interior of V. Conversely, if a <DRM Geometry Node> instance N lies within the interior of V, N shall be associated with V. If no <DRM Geometry Node> instances lie within the interior of V, V shall not be associated with any <DRM Geometry Node> instances.

6.2.7 Continuous LOD constraints

The following constraints apply:

  1. <DRM Continuous LOD Related Geometry> instances can be used only in the scope of some <DRM Environment Root>.
  2. A <DRM Primitive Geometry> instance that is within the component tree of a <DRM Continuous LOD Related Geometry> shall not have a <DRM Union Of Primitive Geometry> component

6.2.8 Corresponding same data type

When the characteristic_value of an instance of class <DRM_Property_Characteristic> corresponds to an actual numerical value such as the UPPER_BOUND, the value shall have the same data type, units, and scale as the attribute being constrained.

6.2.9 Cylindrical structure

For a <DRM Cylindrical Volume Extent> instance C, the following conditions shall hold:

  1. The <DRM Reference Vector> components of C shall comply with the restrictions imposed in the specification of the <DRM Cylindrical Volume Extent> class, including the restrictions on the vector_type field values and the orientation relative to one another.
  2. If a <DRM Reference Vector> component of C specifies a <DRM Location> subclass component L, L shall be the <DRM Location 3D> specified by the volume context in which C appears.

For a <DRM Volume Object> instance E, the following conditions shall hold:

  1. The <DRM Reference Vector> components of E shall comply with the restrictions imposed in the specification of the <DRM Volume Object> class, including the restrictions on the vector_type field values and the orientation relative to one another.
  2. If a <DRM Reference Vector> component of E specifies a <DRM Location> subclass component L, L shall be the <DRM Location 3D> component of E.

6.2.10 Distinct link objects

The following constraints apply to link objects:

  1. Under any single <DRM Aggregate Feature> or <DRM Aggregate Geometry> instance, the link objects (if any) shall have non-identical field values. In the case of <DRM Separating Plane Related Geometry>, this constraint applies to the link objects of the <DRM Separating Plane Relations> components of the aggregate, as the aggregate itself does not have link objects.
  2. Under any single topology hierarchy, whether an instance of <DRM Feature Topology Hierarchy> or <DRM Geometry Topology Hierarchy>, the link objects shall have non-identical field values.
  3. Under any single model instance, whether a <DRM Feature Model Instance> or a <DRM Geometry Model Instance>, the <DRM Model Instance Template Index> instances shall be distinct.

6.2.11 Edges bordering faces

<DRM Feature Edge> instances have the following relationship with <DRM Feature Face> instances:

  1. If a <DRM Feature Edge> instance E associates to a <DRM Feature Face> instance F, E shall be part of one of the <DRM Feature Face Ring> instances of F.
  2. At feature topology level 3 or higher, if a <DRM Feature Edge> instance E is part of any <DRM Feature Face Ring> instance of a <DRM Feature Face> instance F, E shall have an association to F. At lower levels of topology, this relationship may be present, but it is not required.

<DRM Geometry Edge> instances have the following relationship with <DRM Geometry Face> instances:

  1. If a <DRM Geometry Edge> instance E associates to a <Geometry Face> instance F, E shall be part of one of the <DRM Geometry Face Ring> instances of F.
  2. At geometry topology level 3 or higher, if a <DRM Geometry Edge> instance E is part of any <DRM Geometry Face Ring> instance of a <DRM Geometry Face> instance F, E shall have an association to F. At lower levels of topology, this relationship may be present, but it is not required.

6.2.12 Environment_Root spatial reference frame

Consider a <DRM Transmittal Root> instance TR having one or more <DRM Environment Root> instances as components:

  1. For TR, no two <DRM Environment Root> instances may have identical spatial reference frame parameters.
  2. All <DRM Location> instances appearing in the hierarchy rooted at a given <DRM Environment Root> instance shall be specified within the spatial reference frame of that <DRM Environment Root> instance, unless such <DRM Location> instances fall within the scope of an object that specifies its own spatial reference frame, such as a <Property Grid> or <DRM Image Anchor>.
  3. No <DRM Location> instances under a <DRM Environment Root> may be invalid within that spatial reference frame; they shall be either valid, or "extended".

6.2.13 Face_Direction levels 0 - 3

At feature topology levels 0 through 3, the front field of <DRM Face Direction> shall always be true.

6.2.14 Feature_Edge constraints

The following restrictions apply:

  1. The <DRM Location> instances within a <DRM Feature Edge> shall be distinct (that is, no two may have the same coordinates).
  2. <DRM Feature Edge> instances may meet only at <DRM Feature Node> instances, and <DRM Feature Face> instances may meet only along one or more <DRM Feature Edge> instances.
  3. At feature topology level 2 or higher, no <DRM Feature Edge> may intersect with or overlap another <DRM Feature Edge>.
  4. At feature topology level 3, each <DRM Feature Edge> forms part of the boundaries of exactly two <DRM Feature Face> instances.

6.2.15 Face ring edge consistency

The following constraints apply:

  1. For each consecutive <DRM Feature Edge> within a <DRM Feature Face Ring>, and for each consecutive <DRM Geometry Edge> within a <DRM Geometry Face Ring>, the <DRM Edge Direction> shall be consistent with the starting and ending nodes of the edge.
  2. A <DRM Feature Edge> shall appear no more than twice in a <DRM Feature Face Ring>, once with each orientation.
  3. A <DRM Geometry Edge> shall appear no more than twice in a <DRM Geometry Face Ring>, once with each orientation.

6.2.16 Hierarchy summary constraints

The following constraints apply:

  1. An instance of <DRM Hierarchy Summary Item> shall have a drm_class field value corresponding to one of the following:
    1. <DRM Feature Hierarchy> or one of its subclasses, or
    2. <DRM Geometry Hierarchy> or one of its subclasses.
  2. For any <DRM Hierarchy Summary Item> instance B that is a component of another <DRM Hierarchy Summary Item> instance A, the class represented by B’s drm_class field value shall be specified as a formal component of A, and the multiplicity and multiplicity_meaning of B shall comply with the corresponding component relationship between the two classes.
  3. Consider a <DRM Environment Root> instance E,
    1. If E has a <DRM Geometry Hierarchy> component H, E shall have at most one <DRM Hierarchy Summary Item> component S for which the drm_class field corresponds to a <DRM Geometry Hierarchy> subclass. If such a component instance S exists, its field values shall comply with the following constraints:
      1. S’s drm_class shall match that of H.
      2. S’s multiplicity_meaning value shall be EXACT, and its multiplicity field shall have value 1.
    2. If E does not have a <DRM Geometry Hierarchy> component, E shall not have any <DRM Hierarchy Summary Item> component for which the drm_class field corresponds to a <DRM Geometry Hierarchy> subclass.
    3. If E has a <DRM Feature Hierarchy> component H, E shall have at most one <DRM Hierarchy Summary Item> component S for which the drm_class field corresponds to a <DRM Feature Hierarchy> subclass. If such a component instance S exists, its field values shall comply with the constraint
      1. S’s drm_class shall match that of H.
      2. S’s multiplicity_meaning shall be EXACT, and its multiplicity shall have value 1.
    4. If E does not have a <DRM Feature Hierarchy> component, E shall not have any <DRM Hierarchy Summary Item> component for which the drm_class field corresponds to a <DRM Feature Hierarchy> subclass.
    5. Consider a <DRM Model> instance M.
      1. If M has a <DRM Geometry Model> with a <DRM Geometry Hierarchy> component H, M shall have at most one <DRM Hierarchy Summary Item> component S for which the drm_class field corresponds to a <DRM Geometry Hierarchy> subclass. If such a component instance S exists, its field values shall comply with the following constraints.
        1. S’s drm_class shall match that of H.
        2. S’s multiplicity_meaning shall be EXACT, and its multiplicity shall have value 1.
      2. If M does not have a <DRM Geometry Model> component, or its <DRM Geometry Model> does not have a <DRM Geometry Hierarchy> component, M shall not have any <DRM Hierarchy Summary Item> component for which the drm_class field corresponds to a <DRM Geometry Hierarchy> subclass.
      3. If M has a <DRM Feature Model> with a <DRM Feature Hierarchy> component H, M shall have at most one <DRM Hierarchy Summary Item> component S for which the drm_class field corresponds to a <DRM Feature Hierarchy> subclass. If such a component instance S exists, its field values shall comply with the following constraints.
        1. S’s drm_class shall match that of H.
        2. S’s multiplicity_meaning shall be EXACT, and its multiplicity shall have value 1.
      4. If M does not have a <DRM Feature Model> component, or its <DRM Feature Model> does not have a <DRM Feature Hierarchy> component, M shall not have any <DRM Hierarchy Summary Item> component for which the drm_class field corresponds to a <DRM Feature Hierarchy> subclass.
    6. All <DRM Geometry Hierarchy> associates (or <DRM Feature Hierarchy> associates) of a given <DRM Hierarchy Summary Item> instance shall be instances of the class specified by its drm_class field value, and shall conform to the structure that it specifies.

6.2.17 Homogeneous light rendering properties

A <DRM Light Rendering Properties> may only contain one subclass of <DRM Directional Light Behaviour>.

6.2.18 Image_Anchor spatial reference frame

Consider a <DRM Image Anchor> instance X.

  1. The <DRM Location> instances in the scope of X shall be valid or “extended” within the spatial reference frame specified by X's srf_parameters.
  2. X shall be either a component of one or more <DRM Image> instances or of one or more <DRM Image Mapping Function> instances, but not both.
  3. If X is a component of a <DRM Image Mapping Function> instance F, and if F appears within the context of some spatial reference frame S, X's srf_parameters shall equal those specified by S.

6.2.19 Image mapping functions and texture coordinates

The number of <DRM Image Mapping Function> instances an instance of a concrete subclass of <DRM Geometry Representation> has shall be equal to the number of <DRM Texture Coordinate> instances for each <DRM Vertex> instance and <DRM Tack Point> instance within that instance of a concrete subclass of <DRM Geometry Representation>.

<DRM Image Mapping Function> instances for instances of a concrete subclass of <DRM Feature Representation>, on the other hand, shall either have <DRM Image Anchor> components, or specify <DRM Image> instances that have <DRM Image Anchor> components.

EXCEPTION:
If a <DRM Image Mapping Function> instance is used to specify a non-planar projection (e.g., spherical or cylindrical) it shall use a <DRM Image Anchor> component, and the instance of a concrete subclass of <DRM Geometry Representation> to which the <DRM Image Mapping Function> instance is attached cannot have <DRM Texture Coordinate> instances or a <DRM Tack Point> instance.

6.2.20 Index_Codes within tables

The following constraints apply:

  1. No <DRM Property> instance, other than a <DRM Table Property Description> instance, shall have an Index_Code meaning value.

  2. Consider a <DRM Data Table> instance DT, with a component <DRM Table Property Description> instance X, where X has a meaning value of DATA_TABLE_LIBRARY.

    For each corresponding cell value N in the <DRM Data Table> instance D, if N is not a sentinel value for missing or excluded, N is an index into the ordered set of <DRM Data Table> components of a <DRM Data Table Library> instance where:

    1. The transmittal in which the <DRM Data Table> instance D resides shall have a <DRM Data Table Library> instance L,
    2. The <DRM Data Table Library> instance L shall have at least N ordered <DRM Data Table> components, and
    3. The Nth <DRM Data Table> component of the <DRM Data Table Library> instance L shall have a <DRM Classification Data> instance whose tag matches the component_data_table_ecc of the <DRM Table Property Description> instance X.
      1. If the <DRM Classification Data> instance of the referenced Nth <DRM Data Table> instance has no component <DRM Property Value> instances, the<DRM Table Property Description> instance X shall have none.
      2. If the <DRM Classification Data> instance of the referenced Nth <DRM Data Table> instance has j component <DRM Property Value> instances, the <DRM Table Property Description> instance X shall have exactly j matching <DRM Property Value> instances.
  3. Consider a <DRM Data Table> instance D, with a component <DRM Table Property Description> instance X, where X has a meaning Index_Code value of DATA_TABLE_COMPONENT.

    For each corresponding cell value N in the <DRM Data Table> instance D, if N is not a sentinel value for missing or excluded, N is an index into the ordered set of <DRM Data Table> components of D, where:

    1. The <DRM Data Table> D shall have at least N ordered <DRM Data Table> components,
    2. The Nth <DRM Data Table> component of D shall have a <Classification Data> instance whose tag matches the component_data_table_ecc of the <DRM Table Property Description> instance X.
      1. If the <DRM Classification Data> instance of the referenced Nth <DRM Data Table> instance has no component <DRM Property Value> instance, the <DRM Table Property Description> instance X shall have none.
      2. If the <DRM Classification Data> instance of the referenced Nth <DRM Data Table> instance has j component <DRM Property Value> instances the <DRM Table Property Description> instance X shall have exactly j matching <DRM Property Value> instances.

  4. Consider a <DRM Data Table> instance D, with a component <DRM Table Property Description> instance X, where X has a meaning Index_Code value of PROP_TABLE_REF_COMPONENT.

    For each corresponding cell value N in the <DRM Data Table> instance D, if N is not a sentinel value for missing or excluded, N is an index into the ordered set of <DRM Property Table Reference> components of D, where:,

    1. The <DRM Data Table> instance D shall have at least N ordered <DRM Property Table Reference> components,
    2. The Nth <DRM Property Table Reference> component of D shall refer to a <DRM Property Table> instance whose <DRM Classification Data> instance with a tag field that matches the component_data_table_ecc of the <DRM Table Property Description> instance X.
      1. If the <DRM Classification Data> of the referenced <DRM Property Table> has no component <DRM Property Value> instances, the <DRM Table Property Description> instance X shall have none.
      2. If the <DRM Classification Data> instance of the referenced <DRM Property Table> instance has j component <DRM Property Value> instances, the <DRM Table Property Description> instance X shall have exactly j matching <DRM Property Value> instances.
  5. A <DRM Table Property Description> instance that is not covered by b, c, or d above shall have ECC_OBJECT as its component_data_table_ecc value.
  6. Consider a <DRM Data Table> instance D, with a component <DRM Table Property Description> instance X where X has an EAC as its meaning. If X has <DRM Property Value> components, they shall exist to qualify the meaning of X such that X is considered unique among the <DRM Table Property Description> components of DT if its qualified meaning is unique among them.
  7. A <DRM Table Property Description> instance that is not covered by b, c, d, or f above shall have no <DRM Property Value> components.

  8. Consider a <DRM Data Table> instance D, with a component <DRM Table Property Description> instance X, where X has a meaning Index_Code value of IMAGE_MAPPING_FUNCTION.

    For each corresponding cell value N in the <DRM Data Table> instance D, if N is not a sentinel value for missing or excluded, N is an index into the ordered set of <DRM Image Mapping Function> components of D, where the <DRM Data Table> instance D shall have at least N ordered <DRM Image Mapping Function> components.

6.2.21 Inheritance rule for Location

Given any object that has a <DRM Location> component, that <DRM Location> component (or the first <DRM Location> component in an ordered list of <DRM Location> components) becomes the (default) <DRM Location> component in the context for the aggregation tree stemming from that object.

6.2.22 Level of detail related organizing principle

For any level of detail related organization L, whether a <DRM LOD Related Features> or <DRM LOD Related Geometry>:

  1. The instance of a concrete subclass of <DRM Base LOD Data> for each branch of L shall match the class specified by L’s lod_data_type field.
  2. For each pair of branches, if the instances of a concrete subclass of <DRM Base LOD Data> overlap, neither shall be a subset of the other.
    1. For instances of <DRM Distance LOD Data>, neither interval shall be contained within the other. Specifically:
      1. The ranges may touch at their endpoints; that is, the minimum_range of one may equal the maximum_range of the other.
      2. If the ranges overlap by more than one endpoint, each shall have at least one fade band, so that one is fading in while the other is fading out for the overlap range.
    2. For instances of <DRM Volume LOD Data>:
      1. If the two branches both have outside = FALSE, neither volume may be contained within the other.
      2. The volumes specified may be identical if the link objects specify different values for their outside fields, provided that L complies with the constraint specified in 6.2.10 Distinct link objects.
  3. If L inherited a <DRM Base LOD Data> instance C as a component, such that C matches its lod_data_type, L’s link objects shall fall within the scope specified by C:
    1. If C is a <DRM Distance LOD Data> and L is of type DISTANCE, each link object specified by L shall specify a range within the region covered by C.
    2. If C is a <DRM Volume LOD Data> and L is of type VOLUME, each link object specified by L shall specify a volume lying within that of C.
    3. No other classes of C permit a matching L to occur in their inheritance tree.

6.2.23 LSR model and reference surfaces

A <DRM Model> specified using an LSR spatial reference frame (SRF) may not contain (aggregate) any <DRM Reference Surface> instances.

6.2.24 LSR_Transformation components

An <DRM LSR Transformation> instance L shall have a <DRM Local 4x4>, an ordered set of <DRM LSR Transformation Step> components, or both. If L has both a <DRM Local 4x4> and a set of <DRM LSR Transformation Step> components, the ordered set of <DRM LSR Transformation Step> components shall be mathematically equivalent to the <DRM Local 4x4>.

6.2.25 Mandatory metadata

Table 6.2 lists metadata classes. When these classes are instanced, at least the designated fields shall be populated.

Table 6.2 — Mandatory metadata

<DRM Access>

Consider a <DRM Access> instance A.

  1. If A's access_constraints is set to OTHER_CONSTRAINTS. A's other_constraints field shall contain a non-empty string specifying what those other constraints are.
  2. If A's use_constraints is set to OTHER_CONSTRAINTS. A's other_constraints field shall contain a non-empty string specifying what those other constraints are.

<DRM Browse Media>

The field name shall specify a non-empty string.

The field media_urn shall be a valid URN.

<DRM Citation>

The field title shall be a non-empty string.

<DRM Description>

The field abstract shall be a non-empty string

<DRM Keywords>

The field keyword_array shall be non-NULL.

For each entry in keyword_array, the thesaurus field shall contain a non-empty string. To indicate that no thesaurus is applicable, the thesaurus field shall have the value NONE.

For each entry in keyword_array, the keyword_list shall be a non-empty string, where keywords are separated by semicolons.

For any two entries in keyword_array, either the code fields or the thesaurus fields shall have different values.

<DRM Lineage>

An instance of <DRM Lineage> shall specify at least one of the following:

  1. a <DRM Process Step>,
  2. a <DRM Source>, or
  3. a non-empty string within its statement field.

<DRM Responsible Party>

The locale of each String field within a <DRM Responsible Party> instance shall be specified using the same country code as that specified by its address field.

At least one of the following fields shall contain a non-empty string:

  1. individual_name,
  2. position_name, or
  3. organization_name.

The voice_phone field of the Contact_Information value shall be a non-empty string.

The email_address field of the Contact_Information value shall contain a comma-separated list of syntactically valid e-mail addresses.

The web_site field of the Contact_Information> value, if specified, shall contain a comma-separated list of syntactically valid URLs.

At least one of the following shall be a non-empty string:

  1. individual_name,
  2. position_name, and/or
  3. organization_name.

email_address shall be a non-empty string, and shall be a comma-separated list of syntactically valid email addresses

web_site, if specified, shall be a comma-separated list of syntactically valid URLs

The locale of each String field within an instance of <DRM Responsible Party> shall be specified using the same country code as that used by the address except as noted above.

<DRM Process Step>

Given an instance P of <DRM Process Step>, the following conditions shall hold:

  1. P’s description field shall be a non-empty string.
  2. P’s <DRM Absolute Time> component shall have a time_significance value of OCCURRENCE.
  3. If P has <DRM Responsible Party> components, each shall specify PROCESSOR as its role.

<DRM Source>

The description field value shall be a non-empty string.

6.2.26 Model reference type constraints

The following constraints apply:

  1. If an instance of <DRM Model> has model_reference_type value set to ROOT or ROOT_AND_COMPONENT, the <DRM Model> instance’s name shall be unique in the scope of its aggregate <DRM Model Library>.
  2. If an instance of <DRM Model> has model_reference_type set to COMPONENT, the following also apply:
    1. Any <DRM Geometry Model Instance> or <DRM Feature Model Instance> referencing that <DRM Model> shall be in the scope of another <DRM Model> instance;
    2. Its dynamic_model_processing flag shall be FALSE.

6.2.27 Model spatial reference frame

The following constraints apply:

  1. Consider a <DRM Model> instance M specified in a spatial reference frame other than Local Space Rectangular.
    1. M shall be instanced only by <DRM Geometry Model Instance> and/or <DRM Feature Model Instance> instances specified in a matching spatial reference frame, and
    2. M’s has_moving_parts field shall be set to FALSE.
  2. Consider a <DRM Model> instance M specified in a Local Space Rectangular spatial reference frame.
    1. If M’s has_units field is set to FALSE, M shall not be referenced by any <DRM Geometry Model Instance> or <DRM Feature Model Instance> instances.
    2. If M is to be instanced into a non-LSR reference frame by any <DRM Geometry Model Instance> or <DRM Feature Model Instance> instances, each such <DRM Geometry Model Instance> instance and <DRM Feature Model Instance> instance shall specify a <DRM World Transformation> instance.
    3. M cannot be instanced into another Local Space Rectangular reference frame unless the target spatial reference frame has identical parameters to the parameters of M.
    4. If the component hierarchy of M contains any <DRM LSR Transformation> instances that have <DRM Control Link> instances, and if M provides controlling <DRM Variable> instances to those <DRM Control Link> instances such that they allow motion, M’s has_moving_parts field shall be set to TRUE; otherwise, M’s has_moving_parts field shall be set to FALSE.
  3. All <DRM Location> instances under a <DRM Model> instance shall be expressed in the spatial reference frame specified by that <DRM Model> instance.

6.2.28 Nested primitive geometry

When a <DRM Primitive Geometry> instance contains a <DRM Union Of Primitive Geometry> instance, for nesting reasons, the resulting geometry shall be coplanar.

The possible combinations at any level of nesting are:

6.2.29 Non-crossing aggregations

Aggregations cannot cross <DRM Model> instances and/or <DRM Environment Root> instances.

6.2.30 Non-crossing associations

Associations cannot cross <DRM Model> instances and/or <DRM Environment Root> instances, except for <DRM Geometry Model Instance> instance to <DRM Geometry Model> instance, and <DRM Feature Model Instance> instance to <DRM Feature Model> instance.

6.2.31 Non-cyclic aggregations

Aggregations are not allowed to form cycles. Associations are. By this rule:

  1. an object can associate to itself; e.g., a <DRM Point Feature> can associate with itself;
  2. a <DRM Feature Representation> instance can associate to a <DRM Geometry Hierarchy> instance that associates to the <DRM Feature Representation>; and
  3. an object cannot have itself as a component.

6.2.32 Non-empty Environment_Root

An <DRM Environment Root> shall have as components a <DRM Feature Hierarchy> and/or a <DRM Geometry Hierarchy> instance.

6.2.33 Non-empty Model

The following constraints apply:

  1. All <DRM Model> instances shall have either a <DRM Feature Model>, a <DRM Geometry Model>, or both.
  2. A <DRM Model> is permitted to have an empty <DRM Geometry Model>, that is, a <DRM Geometry Model> without a component <DRM Geometry Hierarchy>, only if:
    1. The <DRM Model> either does not have a <DRM Feature Model>, or its <DRM Feature Model> is empty;
    2. The <DRM Model> has a <DRM Classification Data> component with tag set to ECC_OBJECT;
    3. The <DRM Model> is tagged as ROOT_AND_COMPONENT so that it can be instanced within <DRM Environment Root> scopes as well as other <DRM Model> instances; and
    4. The empty <DRM Geometry Model> has no <DRM Attachment Point>, <DRM Contact Point>, or <DRM LSR Transformation> component, since these components require the presence of a <DRM Geometry Hierarchy> instance.
  3. A <DRM Model> is permitted to have an empty <DRM Feature Model>, that is, a <DRM Feature Model> without a <DRM Feature Hierarchy> component, only if:
    1. The <DRM Model> either does not have a <DRM Geometry Model>, or its <DRM Geometry Model> is empty;
    2. The <DRM Model> has a <DRM Classification Data> component with tag set to ECC_OBJECT; and
    3. The <DRM Model> is tagged as ROOT_AND_COMPONENT so that it can be instanced within <DRM Environment Root> scopes as well as other <DRM Model> instances.
  4. No <DRM Model> other than a properly constructed empty <DRM Model> is permitted to have a <DRM Classification Data> with ECC_OBJECT

6.2.34 Non-overlapping DRM class summary items

In a list of <DRM DRM Class Summary Item> instances, no two shall have their type fields set to the same class type.

6.2.35 Non-selfoverlapping perimeter data locations

The perimeter specified by a <DRM Perimeter Data> instance shall not intersect with or overlap itself.

6.2.36 No property conflicts

The following restrictions apply:

  1. No two directly attached <DRM Property Value> components of an object instance may specify identical values for their meaning fields.

    If an inherited <DRM Property Value> has the same meaning field value as a directly attached <DRM Property Value>, the directly attached component replaces the inherited component in the inheritance context.

  2. No two directly attached <DRM Property Description> components of an object instance may specify identical values for their meaning fields.

    If an inherited <DRM Property Description> has the same meaning field value as a directly attached <DRM Property Description>, the directly attached component replaces the inherited component in the inheritance context.

6.2.37 Octant related organizing principle

For any oct tree-related organization O, whether a <DRM Octant Related Geometry> or a <DRM Octant Related Features> instance,

  1. O shall have a <DRM Spatial Extent> component, specifying the bounding volume that the oct tree is organizing into octants. Since a volume is being specified, this <DRM Spatial Extent> shall be specified in terms of <DRM Location 3D> components.
  2. Each branch of O shall comply with the following constraints:
    1. Each component representing an octant shall have a <DRM Spatial Extent> component. In the case of octants represented by <DRM Geometry Model Instance> or <DRM Feature Model Instance> instances, the <DRM Model> instance being referenced shall have the <DRM Spatial Extent> component. Since a subdivision of a volume is being specified, this <DRM Spatial Extent> instance shall be specified in terms of <DRM Location 3D> instances.
    2. The regions specified by the branches shall not overlap; that is, the corresponding <DRM Spatial Extent> instances shall not overlap.
    3. The eight possible octant components' <DRM Spatial Extent> instances shall be specified in their native SRF within the area specified by the O's <DRM Spatial Extent> instance as shown in Figure 5.3. Consider the bounding area specified by the <DRM Spatial Extent> instance of O, as divided into eight octants of equal size with the area specified from point “a” to point “o” in Figure 5.3.
    4. If a branch with UPPER_NORTHWEST is present, its <DRM Spatial Extent> instance shall specify the area of the upper northwest octant, from point “h” to point “o” in Figure 5.3, such that:
      1. its eastern boundary aligns with the western boundary of the UPPER_NORTHEAST octant’s <DRM Spatial Extent> instance, if present;
      2. its southern boundary aligns with the northern boundary of the UPPER_SOUTHWEST octant’s <DRM Spatial Extent> instance, if present; and
      3. its lower boundary aligns with the upper boundary of the LOWER_NORTHWEST octant’s <DRM Spatial Extent> instance, if present.
    5. If a branch with UPPER_NORTHEAST is present, its <DRM Spatial Extent> instance shall specify the area of the upper northeast octant, from point “g” to point “n” in Figure 5.3, such that:
      1. the <DRM Location 3D> instance representing its upper northeast corner corresponds to that of O's <DRM Spatial Extent> instance;
      2. its western boundary aligns with the eastern boundary of the UPPER_NORTHWEST octant’s <DRM Spatial Extent> instance, if present, and its southern boundary aligns with the northern boundary of the UPPER_SOUTHEAST octant’s <DRM Spatial Extent> instance, if present; and
      3. its lower boundary aligns with the upper boundary of the LOWER_NORTHEAST octant’s <DRM Spatial Extent> instance, if present.
    6. If a branch with UPPER_SOUTHWEST is present, its <DRM Spatial Extent> instance shall specify the area of the southwest octant, from point “f” to point “m” in Figure 5.3, such that:
      1. its eastern boundary aligns with the western boundary of the UPPER_SOUTHEAST octant’s <DRM Spatial Extent> instance, if present;
      2. its northern boundary aligns with the southern boundary of the UPPER_NORTHWEST octant’s <DRM Spatial Extent> instance, if present; and
      3. its lower boundary aligns with the upper boundary of the LOWER_SOUTHWEST octant’s <DRM Spatial Extent> instance, if present.
    7. If a branch with UPPER_SOUTHEAST is present, its <DRM Spatial Extent> instance shall specify the area of the southeast octant, from point “e” to point “l” in Figure 5.3, such that:
      1. its western boundary aligns with the eastern boundary of the UPPER_SOUTHWEST octant’s <DRM Spatial Extent> instance, if present;
      2. its northern boundary aligns with the southern boundary of the UPPER_NORTHEAST octant’s <DRM Spatial Extent> instance, if present; and
      3. its lower boundary aligns with the upper boundary of the LOWER_SOUTHEAST octant’s <DRM Spatial Extent> instance, if present.
    8. If a branch with LOWER_NORTHWEST is present, its <DRM Spatial Extent> instance shall specify the area of the upper northwest octant, from point “d” to point “k” in Figure 5.3, such that:
      1. its eastern boundary aligns with the western boundary of the LOWER_NORTHEAST octant’s <DRM Spatial Extent> instance, if present;
      2. its southern boundary aligns with the northern boundary of the LOWER_SOUTHWEST octant’s <DRM Spatial Extent> instance, if present; and
      3. its upper boundary aligns with the lower boundary of the UPPER_NORTHWEST octant’s <DRM Spatial Extent> instance, if present.
    9. If a branch with LOWER_NORTHEAST is present, its <DRM Spatial Extent> instance shall specify the area of the upper northeast octant, from point “c” to point “j” in Figure 5.3, such that:
      1. its western boundary aligns with the eastern boundary of the LOWER_NORTHWEST octant’s <DRM Spatial Extent> instance, if present;
      2. its southern boundary aligns with the northern boundary of the LOWER_SOUTHEAST octant’s <DRM Spatial Extent> instance, if present; and
      3. its upper boundary aligns with the lower boundary of the UPPER_NORTHEAST octant’s <DRM Spatial Extent> instance, if present.
    10. If a branch with LOWER_SOUTHWEST is present, its <DRM Spatial Extent> instance shall specify the area of the southwest octant, from point “b” to point “i” in Figure 5.3, such that:
      1. the <DRM Location 3D> instance representing its lower southwest corner corresponds to that of O's <DRM Spatial Extent> instance;
      2. its eastern boundary aligns with the western boundary of the LOWER_SOUTHEAST octant’s <DRM Spatial Extent> instance, if present;
      3. its northern boundary aligns with the southern boundary of the LOWER_NORTHWEST octant’s <DRM Spatial Extent> instance, if present; and
      4. its upper boundary aligns with the lower boundary of the UPPER_SOUTHWEST octant’s <DRM Spatial Extent> instance, if present.
    11. If a branch with LOWER_SOUTHEAST is present, its <DRM Spatial Extent> shall specify the area of the southeast octant, from point “a” to point “h” in Figure 5.3, such that:
      1. its western boundary aligns with the eastern boundary of the LOWER_SOUTHWEST octant’s <DRM Spatial Extent>, if present;
      2. its northern boundary aligns with the southern boundary of the LOWER_NORTHEAST octant’s <DRM Spatial Extent>, if present; and
      3. its upper boundary aligns with the lower boundary of the UPPER_SOUTHEAST octant’s <DRM Spatial Extent>, if present.
  3. The strict_organizing_principle and unique_descendants field values of O shall be TRUE.

6.2.38 Perimeter related feature topology partitioning

The following conditions apply to DRM_Perimeter_Related_Feature_Topology DRM class instances:

  1. The regions specified by the components of a DRM_Perimeter_Related_Feature_Topology object shall not overlap.
  2. A DRM_Feature_Topology object may belong to at most one DRM_Perimeter_Related_Feature_Topology instance.

6.2.39 Perimeter related organizing principle

The following constraints apply:

  1. For any perimeter-related organization,
    1. The regions specified by its branches shall not overlap; that is, the <DRM Perimeter Data> on the branches shall specify regions that do not overlap.
    2. For each branch of the organization, every primitive within that branch shall have a spatial extent overlapping that of the branch.
  2. For topological organizations:
    1. A <DRM Feature Topology> instance shall belong to at most one <DRM Perimeter Related Feature Topology> instance.
    2. A <DRM Geometry Topology> instance shall belong to at most one <DRM Perimeter Related Geometry Topology> nstance.
  3. Consider a perimeter-related organization P, which is either <DRM Perimeter Related Features> instance or a <DRM Perimeter Related Geometry> instance.
    1. If P’s strict_organizing_principle field has value TRUE, for each branch of P, each primitive within the branch shall have a spatial extent fully contained within that specified by the <DRM Perimeter Data> instance corresponding to the branch.
    2. If P’s strict_organizing_principle has value FALSE, no guarantees exist as to how accurately the objects of the component tree rooted at P were placed into their sorted bins (that is, the branches of P), apart from that specified by a.1 above.
    3. If P is a <DRM Perimeter Related Features>, and the same <DRM Feature Representation> instance belongs to more than one of its branches, the unique_descendants and strict_organizing_principle flags of P shall be set to FALSE.
    4. If P is a <DRM Perimeter Related Geometry>, and the same <DRM Geometry Representation> instance belongs to more than one of its branches, the unique_descendants and strict_organizing_principle fields of P shall be set to FALSE.

6.2.40 Precedence of Property_Set_Index

Instances of concrete subclasses of <DRM Geometry Representation> or <DRM Feature Representation> may contain attribute and/or metadata objects and also <DRM Property Set Index> objects that refer to <DRM Property Set> objects. If there is a clash between the attribute or metadata objects that are contained by the instance of a concrete subclass of <DRM Geometry Representation> or <DRM Feature Representation> and any attribute or metadata objects that are contained by <DRM Property Set> objects, objects contained directly by instances of concrete subclasses of <DRM Geometry Representation> or <DRM Feature Representation> take precedence.

DRM Geometry Representation and <DRM Feature> instances may contain an ordered list of <DRM Property Set Index> instances. If a <DRM Geometry> or <DRM Feature> contains references to more than one <DRM Property Set> and there is a clash between the property objects they contain, property objects contained in <DRM Property Set>s referenced first in this ordered list have precedence over those contained in <DRM Property Set> instances that are referenced later.

Precedence will behave differently depending on the multiplicity of the relationship that the attribute or metadata object in question has with the containing <DRM Geometry> or <DRM Feature>. In the event of a clash, the following rules will apply based on this enumeration.

  1. Zero or one:
    The object contained directly by the <DRM Geometry> or <DRM Feature> is used. If the clash is between objects in <DRM Property Set> s, the object contained in the <DRM Property Set> that is referenced earliest in the list of <DRM Property Set Index> objects is used.
  2. Zero or more:
    Those objects contained directly by the <DRM Geometry> or <DRM Feature> instances are used, followed by those contained in the <DRM Property Set> instances, in the order that the <DRM Property Set> instances are referenced by the <DRM Geometry> or <DRM Feature> instances.
  3. Zero or more {ordered}:
    Those objects contained directly by the <DRM Geometry> or <DRM Feature> instances are used in order. Those contained in the <DRM Property Set> instance referenced by the first <DRM Property Set Index> object in the list are used, in order followed by those contained in the <DRM Property Set> instance referenced by the second <DRM Property Set Index> object in the list, in order.

This is continued until there are no further objects in the list.

6.2.41 Primitive summary item constraints

The following constraints apply:

  1. An instance of <DRM Primitive Summary Item> shall have a drm_class field value corresponding to one of the following:
    1. <DRM Primitive Feature> or one of its subclasses,
    2. <DRM Primitive Geometry> or one of its subclasses, or
    3. classes that may legally appear in the component tree of a <DRM Primitive Feature> or <DRM Primitive Geometry> instance.
  2. For any <DRM Primitive Summary Item> instance B that is a component of another <DRM Primitive Summary Item> instance A, the drm_class represented by B shall be specified as a formal component of A, and the multiplicity of B shall comply with the corresponding component relationship between the two classes.
  3. For any <DRM Primitive Summary Item> component S of a <DRM Environment Root> instance ER, where the drm_class field corresponds to a class P, the component tree of ER shall contain at least one instance of P, either in its <DRM Feature Hierarchy> instance, its