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OneSpace Designer: ME10 Dynamic Drafting MI Interfacing


Assembly Hierarchy Section (#~5)

The Assembly Hierarchy section contains Assembly entities (ASSE) relating to all the parts in the MI model. There will be one ASSE for each part.

ASSEs contain information about details of any shared parts, and provide transformation matrices for producing images of shared parts. For more information on matrices, refer to "General Reference Data" and "Transformation Matrices" in General Reference Data and to Appendix A.

The Assembly Hierarchy section specifies the number of parts within the drawing, and the parts structure. For a discussion of parts, refer to ME10 User's Guide.

The ASSEs entities point to a part definition by using the part name, and use pointers to other ASSEs to determine the parts structure. The ASSE also contains pointers to properties, for example to establish Part Status information.

There can be only one Assembly Hierarchy section in an MI file, and this section contains all the ASSEs. There must be at least one ASSE that lies at the top of a tree structure, with pointers to its subordinate ASSEs. All pointers to subordinate ASSEs are to immediate subordinates (children, but not grandchildren).

It is possible to have multiple instances of a subpart. This means that the subpart can be displayed in different positions and attitudes on the screen. In this case, the parent ASSE has more than one pointer to the ASSE corresponding to the subpart. Different transformation matrices are then applied to produce different images on the screen. Refer to Example 1 in Overview of MI, "Overview of MI".

ASSE (Assembly Hierarchy Entity)

The pointer tree and entity description are given in the following paragraphs.

Pointer Tree


Figure 34. Pointer Tree for ASSE

The ASSE also points to the part definition by using the part name. This is the only case of a "forwards" pointer in MI. All other pointers point "backwards" to earlier entries in the MI file.

Identification Data

ASSE Entity Type.
n+ Entity Sequence Number.

Attribute Data

No Attribute Data.

Property Data

n+ Property Count.

PTR First Property Pointer.
: 
PTR Last Property Pointer.

Parameter Data

STRING Part Name. This is a pointer to the first section in a part definition.

REAL Drawing scale of part.

REAL Offset Vector X Value.

REAL Offset Vector Y Value.

REAL Offset Vector Z Value. This item will only exist if the Global Space Flag in the Setup section of the MI file is set to 3D.
REAL Reference Point X Value.

REAL Reference Point Y Value.

REAL Reference Point Z Value. This item will only exist if the Global Space Flag in the Setup section of the MI file is set to 3D.

n+ Number of Subordinate ASSEs. This will only include ASSEs that are the next level down in the parts tree structure.

If the number of subordinate ASSEs is 0, the entity definition ends here. Otherwise, the following items, as far as the end-of-entity delimiter, are repeated for each subordinate ASSE.
n+ Attribute 1 (Virtual Offset for subordinate ASSE).
n+ Attribute 2.
n+ Attribute 3.
  Attribute 1 is used for the sequence number of the first entity of a virtual part. For an explanation of virtual parts see the section on dimension entities. Attribute 2 and 3 are not used in this revision of MI, but are reserved for future use.
n+ Property Count.
PTR First Property Pointer.
:  
PTR Last Property Pointer.
  The property pointers may include a pointer to an Associated Text Property (ASSP), and this information is applied to the part corresponding to the subordinate ASSE.
PTR Pointer to Subordinated ASSE.
9×REAL Transformation Matrix (3x3) to be applied to the subordinate ASSE, to obtain a visualization of the contents of the corresponding part.
  If the visualization is to remain unchanged, the matrix will be an identity matrix, with all the diagonal elements equal to 1 and the other elements equal to 0.
  See Appendix A, Transformation Matrices.

All the above items, after the Number of Subordinate ASSEs, are repeated for each Subordinate ASSE.

n+ Unique parts name/number of subparts where PTR points to.

|~ End of Entity.


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