Comparison and Merge Processes

The Import, Comparison and Merge process involves three stages. First, the model is imported. You then have the option of comparing the imported model with the original model, after which you may merge the new data into the old model, or the comparison and merge process can be performed as one with no interaction. Though you can tell the system to Import, Compare and Merge the model straight away this should only be performed if you are sure of the end result. It is advised that you Compare the models first and inspect the results before Merging.

You can decide to keep the imported reference model, but are warned that this is only to be regarded as transitory information. It may also not be a complete representation of the data imported as some of it is transferred to the real design area.

If the target area is empty, the Compare/Merge processes are bypassed which can be a lot faster when importing large amounts of data.

The Comparison Process

There are three conditions the AVEVA SDNF looks for:

• items in the imported file that are not in the original model - Added items;

• items in the original model that are not in the imported file - Deleted items;

• items that it can match between the imported file and the original model and checks for modifications - Changed items.

The fact that an item is in the imported file and not in the original model is indicative of one of two cases: that the item has indeed been added by the external steel detailing package; or that the item was never exported in the first place for some reason. The latter case might also occur if the original model has had items added to it since the export happened. Further, items may appear to have been deleted and their clones imported when the import store location is not the same as it was for the export process.

The diagram illustrates the route through which the data is imported, compared and merged. New items are green, changed items are orange and deleted items are red.

The interface supports partial model transfer as it just identifies those new or changed items. Anything indicated as deleted is more an indication that the item is not present in the Imported SDNF file. It is not deleted from the Original Model during the Merge process: "Deleted" items are moved to another SITE to enable you to recover them if necessary. So parts of models can be merged into the original model with no loss of data.

Note:
The Reference Model which is created is named according to the user session, so that several Reference Models can coexist at the same time. As they are named according to session, you are advised to take care to manage them and not to leave too many versions around to fill up disk space.

The Comparison process allows any potential changes, additions and deletions to the original model to be detected and enhanced in a 3D view, if there is one present and if the items are in the current Drawlist.

As for both Linear Members and Plates you can select which attributes are significant for Comparison. The Comparison Checklist window which is a child of the Import Run Information window allows for this. By default, all the attributes transferred through the SDNF file are compared.

Compare Linear Members

The detailed data attributes are compared between the original model and the reference model:

• Start and end of Pline defined by Cardinal Point

• Orientation and Beta angle

• Specification Reference

• Start and End releases

• Material grade and reference

• Hold and Paint Spec UDAs

• Fireproofing data

Importing a Linear Member also sets the Import date and time UDAs. On merging members the revision number, transfer number and code are updated.

The log file messages recording any differences are of two formats: in Brief mode the results are presented on one line; in Verbose mode you are told what the old value was and the new value is so that you can view how the model has been changed. Details about the brief log file format are available. Refer to Brief Format for further information.

You may get a lot of apparent changes which may be caused by the failure to map the profile types between systems. The log file indicates which profiles have not been mapped. It is advised that you resolve the Profile Mapping issues first before becoming too concerned with other changes recorded in the log file.

During the Import phase, an attempt is made to map the SDNF Cardinal Points in the incoming model with existing Plines that have been mapped onto them.

Compare Plates (PANE)

The detailed data attributes are compared between the original model and the reference model:

• Position, orientation

• Material grade and reference

• Hold and Paint Spec UDAs

• Panel loop height and justification

• Number of vertices

• Fireproofing data

Vertex positions are compared to within the user definable tolerance as described in the section on user customization of the interface.

Importing a Plate also sets the Import date and time UDAs. On merging members the revision number, transfer number and code are updated.

The log file messages, recording any differences, are of two formats: in Brief mode the results are presented on one line; in Verbose mode you are told what the old value was and the new value is so that you can view how the model has been changed. Details about the brief log file format are available. Refer to Brief Format for further information.

Note:
In Exporting a Plate, it has to be converted to the SDNF standard of being defined in a clockwise direction relative to the plane normal. Thus Importing a Plate previously defined in Model you may find the order of vertices to have been reversed. Model is more tolerant about the ways in which you can define a plate.

We now compare plates with holes as secondary loops (PLOO) or NXTR primitives. We can now merge the imported model including new holes created outside of the application. However, because of the complexity of the comparison process, it is difficult to compare holes between the original and imported model. Where possible all other negative primitives representing holes in the original model are maintained. Therefore the comparison does not go down to the level of holes.

Merge Process

Refer to Comparison and Merge Processes for further information. The diagram illustrates the route by which information is transferred from the Import, through the Comparison and on to the Merging processes.

The AVEVA SDNF interface manages the Comparison and Merging of imported models so that other important engineering data is not lost or overwritten. However, other data, including connectivity may be lost.

You can separate the Comparison and Merging processes, so that you are able to view the log file in between operations. If you choose the Merge from File option on the main SDNF Import window, the Comparison process is deemed to have been completed and all that remains to be done is the actual Merging. The reference model for the current session must still be available. You are prompted for confirmation.

If, during the Merge phase, items are to be merged, the lists of added and deleted items are reconciled with the original model - by being deleted or transferred from the reference model. The storage SITE header details are then merged with the information in the SDNF header (Packet 00).

After the main model Merging has been completed, if you have chosen the Sort on Material Type option on the Import window, any new items are sorted into FRMW groups according to their material type as specified by the :SDNFMGRADE attribute.

The version numbering system is described. Refer to Technical Information for further information.

Additional Items

Items added to the model are recorded as such; they are indicated by changing their colour, a suitable message is output to the log file and they are then transferred to a special area. Merging transfers all the added items from the reference model to the original model. If required, they are then sorted according to material type.

The new items are gathered together into a site whose name is constructed from the Transfer and Revision Numbers so that you can easily locate all items added at a specific version or date.

For example, a new STRU may be created with the name of /SDNF-NEW-DEMO-SYSTEM/A.1 under the container element as specified in the Store in: field on the Import window. The components of this name are:

You would be able to find all the added items to this MDB at this version.

Deleted Items

Deleted items in the model are recorded as deleted during the Compare phase and remain in the reference model to be deleted later if not required. The separation of operations allows you to view items that are deleted during the Merge process. Before deletion the objects are changed in colour so that they may be identified.

Note:
An item is not actually deleted from the original model. The apparent deletion may, in fact, be because the item was never transferred to the external detailing package in the first place due to some reason. Alternatively it may have been created in Model since the initial Export process had taken place.

'Deleted' items are disconnected from the old model and transferred from the current part of the database into a STRU created under the special 'Deleted' SITE.

As with the added items, the STRU is named out of components, thereby enabling you to determine at which version items may have been removed from the model.

For example, a new STRU may be created with the name of /SDNF-OLD-DEMO-SYSTEM/A.1 under the special SITE /SDNF-OLD-DEMO-SYSTEM. The components of this name are:

You would be able to find all the 'deleted' items to this MDB at this version.

Changed Items

In merging Plates, the interface tries to keep the original vertices as they may have been used for locating dimensions on drawings: it may be that just the positions have been changed. However, the comparison only works in list order: the interface does not look around for another vertex in the same physical place, although it may be in a different list position. Extra unwanted vertices are deleted on merging and all new vertices are added to the end of the list. A totally new Plate is just imported directly.

Changed objects are indicated as such by a change in colour.

Error and Warning Messages