Element identifier system

Several different identifiers are provided to identify items in their metadata. Some of them depend on the data source and some of them are generated by the Tangl platform.

# Block of general element properties
Id: <string || number>
Guid: <uuid>
ElementGuid: <uuid>
...
Meta: # Metadata start block
  Element: # Element metadata block
    ...

All elements have the following identifiers at the root of their metadata:

• Id
• ElementGuid
• Guid

In addition, another identifier for the items is created during the process of loading the data into the Tangl viewer:

• ElNum

Id

Internal identifier of the element. Format - string.

Assigned by the source program. Can be a number or other data type.

The identifier is stored as a string, but can have any representation specified by the source. For example, for Revit it will be the internal numeric identifier of the element, and for IFC EntityLabel/ExpressId of the element.

It should be noted that this identifier is unique only within one file and may be repeated in different files or versions of the same file.

ElementGuid

Global element identifier.

Assigned by the source program. The format is a GUID string.

The identifier is provided by the source if available. For example, for Revit it will be the UniqueId of the element and for IFC the GlobalId of the element.

It should be noted that this identifier is unique only within one file and may be repeated in different files or versions of the same file.

Guid

Global item identifier in GUID format.

It is assigned by Tangl system in the process of data export/import. When re-exporting, new identifiers will be generated for items.

This identifier is required to ensure that items are unique across the platform, regardless of file, version, etc.

ElNum

Global numeric item identifier for data/files loaded into the Tangl viewer.

It is assigned to elements in the process of opening data in the viewer. The format is a number.

This identifier is required to ensure uniqueness of elements within the loaded dataset in a separate viewer session and is the main identifier for dividing the scene geometry into elements and working with them.

When data is reloaded into the viewer, items may be assigned different identifiers.