The Internal Block Diagram (ibd) is used to describe the internal structure of a Block's compartment parts (i.e. a subordinate block of the enclosing Block) and how its parts are interconnected, and what flows across the connections. The specified flow items represent high-level internal interfaces. Interactions with external Blocks are also modelled to specify the required external interfaces.
The following ibd has all the possible symbols that can be used:
A real world example ibd is shown below:
SymbolsAn example ibd is:
The symbols available in ibds are:
| Symbol | Name | Description |
|---|---|---|
 | Comment | Makes a note anywhere in the diagram. Are always surrounded by * characters. Note: If you do not want Cradle to automatically add an * go to the Graphics Settings section of Project Setup and turn off the Automatically add asterisks to diagram's comment symbols option. |
 | Picture | Allows you to choose the location of a GIF or JPEG image to be displayed as a diagram symbol. An image can also be embedded in the other diagram symbols. |
 | Note Callout | Multi-purpose symbol which attaches to other symbols in order to show certain attributes of the model element. It can show frames, categories, tags, related items, or simply a piece of standalone text. |
 | Tag | A Tag is used to display a tag value contained in a symbol's stereotype frames, or cross reference link attribute, anchored to the selected symbol. |
 | Part | A Part is an instance of a Block. The Part drawn on an ibd can optionally display the following compartments: Values, Parts, References, Flow Properties, Operations, Constraints, Proxy Ports, Full Ports, Relationships and Structure. All of these compartments except for the structure compartment are filled with elements that are cross referenced to the Part. The structure compartment is a mini ibd drawing area. The compartments are defined as follows:
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 | Reference | A Reference is a Block that is external to the Block hierarchy the parts on the ibd are part of. This symbol has some optional compartments as the part symbol. In the following example the structure compartment of a reference Block is shown. Notice that the reference Block has a dashed border so it is easy to tell it is an external reference Block. |
 | Full Port | A Full Port assigned to a block has a port definition block that defines valid incoming and/or outgoing items. Full Ports are similar to Parts, in that they are included in the parts tree of their owning block. Full Ports can contain nested ports, whose types (i.e. block) can also contain ports. A Full Port can also have nested Proxy Ports. The Full Port must be cross referenced to the owning block with the «has port» relationship. The Full Port is then cross referenced to the Full Port definition block with the «port details» relationship. In the following example there is a Full Port attached to Block Part 4. The Full Port definition Block associated with the Port is named Fuel Line. This Block defines what flow properties passed through the Port:  |
 | Proxy Port | Proxy Port provides access to/from features of its owning Block or its owning Block's nested parts to the outside world. Proxy Ports are typed by an «interfaceBlock» to specify which items operations and signals are accessible to the outside world. The «interfaceBlock» must be cross referenced to the «proxyPort» with the «port details» relationship. Proxy Ports can be nested. Nested Proxy Ports are always shown on the outside boundary of the port symbol. In the following example there is a Proxy Port attached to Block Part 4. The Proxy Port is defined by an «interfaceBlock» stereotype that specifies what flow properties passed through the port.  |
 | Connector | An ibd can be used to show connections between the parts of an enclosing Block, something that cannot be shown on a bdd. Connectors can also connect References and connect Ports. The Connector path can have one or more attached item flow symbols. |
 | Item Flow | Used to specify the items that flow across a connector in a particular context and the direction of flow. It represents a type of matter, energy, or data that flows between two structures within a system. The Name Symbol dialog used to name the item flow symbol has a Referenced Element selection list used to specify the item flow object («valueType», «block» or «signal». |
The symbols along with their default stereotypes, referenced elements, stereotype frames and cross reference link attributes are:
| Symbol | Name | Default Stereotype | Referenced Element | Stereotype Frames or Cross Reference Link Attributes |
|---|---|---|---|---|
| Comment | None | None | None |
| Picture | None | None | None |
| Note Callout | None | None | None |
| Tag | None | None | None |
| Part | «block» | None | None |
| Reference | «block» | None | None |
| Full Port | «fullPort» | None | None |
| Proxy Port | «proxyPort» | None | None |
| Connector | None | None | None |
| Item Flow | «signal» «block» «valueType» | None | «valueType» frames:
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