12d Model Feature Representation

In addition to the generic FME feature attributes that FME Workbench adds to all features (see About Feature Type Attributes), this format also adds format-specific attributes (Format Attributes).

All 12d Model XML features contain a 12dxml_type attribute, which identifies the geometric type. In the rare cases where the model does not actually contain any geometry, the value of this attribute will be 12dxml_no_geom.

Writer Feature Representation

The 12D Model xml writer supports multiple feature types contained in the model element. However, differentiating the output element type based on the feature geometry becomes a challenge. For example, an FMEPath geometry, sequence of line segments, can be interpreted as the path of a road in a string_super element or a network of pipes under a string_drainage element. Thus, to differentiate between the 12d types, the writer looks for specific attributes that relate to the element.

12D Element Type	FME Geometry Type	Required Attributes
string_super	FMEPoint, FMELine, FMEPolygon	None
string_drainage	FMELine, FMEAggregate, FMEPipe	drainage_sewer outfall flow_direction use_pit_con_points
trimesh	FMEMesh	None
tin	FMEMesh	input.preserve_strings input.remove_bubbles input.weed_tin input.triangle_data input.sort_tin input.cell_method

Attributes

12d Model elements have attributes specific to each feature, similar to FME feature attributes. 12d Model attribute types must be one of the following: integer, real, text, or group. Attributes can have a recursive definition by using the group type, which allows for nested attributes going down to any level.

The 12d Model XML reader in dataset mode will dynamically unflatten these attributes into the following feature attributes:

Attribute Name	Attribute Value
Group_A.Attribute_1	Value 1
Group_B.Attribute_2	Value 2
Group_B.Group_C.Attribute_3	Value 3

Vertex and Segment Attributes

A super string can have attributes for the entire string (feature attributes) or have attributes for each vertex and/or segments (geometry attributes). FME does not support having attributes or traits on individual vertex or segments, so vertex and segment attributes are transferred onto feature attributes. Vertex and Segment attributes will contain a prefix Vertex{n} or Segment{n}, where n represents the nth vertex or segment.

This 12d XML reader/writer will read and write Vertex and Segment attributes as the following list attributes:

Attribute Name	Attribute Value
Vertex{0}.attr_A	Fred
Vertex{0}.attr_B	100
Vertex{1}.attr_A	200

Pipe and Pit Attributes

A string drainage feature type represents a network of pipes. Pipe and Pit attributes specific to a single pipe will be set as a list attribute on the feature, similar to Vertex and Segment attributes.

When writing to 12d XML, if pipe or pit list attributes exist for a pipe at index i, then those attributes will be written. Otherwise, only diameter and thickness attributes will be written for the pipe, as well as the ip attribute for the pit.

Geometry Representation

The geometry of 12d Model features is identified by the 12dxml_type attribute. The valid values for this attribute are described below.

Aggregates

12dxml_type	FME Type	Feature Type	Description
12dxml_collection	fme_collection	Aggregate feature	Features with their 12dxml_type set to 12dxml_collection could be an aggregate of vertical and horizontal alignments, or an aggregate of FMEPipe geometries that represent a drainage network. A 12dxml_collection geometry comes from a super_string_alignment or a string_drainage element. For string drainage reading and writing, FME assumes the FMEPipe geometries in the aggregate are connected in the order they appear.

Areas

12dxml_type	FME Type	Feature Type	Description
12dxml_polygon	fme_polygon fme_rectangle fme_rounded_rectangle	Polygon feature	Features with their 12dxml_type set to 12dxml_polygon are polygon features that do not have interior boundaries. A polygon geometry is automatically created when a geometry is detected to be closed. A 12dxml_polygon geometry comes from a string_super element.

Lines

12dxml_type	FME Type	Feature Type	Attribute Type
12dxml_line	fme_line fme_ellipse fme_arc	Linear, arc, or path feature	Features with their 12dxml_type set to 12dxml_line are polyline, arc, and path features. A path feature may contain a combination of straight line and arc geometries. A 12dxml_line geometry comes from a string_super or string_drainage element.

No Geometry

12dxml_type	FME Type	Feature Type	Description
12dxml_no_geom	fme_no_geom	FME feature with no geometry	Features with their 12dxml_type attribute set to 12dxml_no_geom do not contain any geometry data.

Points

12dxml_type	FME Type	Feature Type	Description
12dxml_point	fme_text	Point feature	Features with their 12dxml_type set to 12dxml_point are single coordinate features (also referred to as vertex geometry by 12d Model). A 12dxml_point geometry comes from a string_super element.

Surfaces

12dxml_type	FME Type	Feature Type	Description
12dxm_surface	fme_surface	Surface feature	Features with their 12dxml_type set to 12dxml_surface are triangulated irregular networks (TINs). A 12dxml_surface geometry comes from a full_tin, tin, or primitive_3d element.