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Groups

A group contains a defined selection of objects. Whether and which objects are associated with a group is determined by the string „Expression“ referring to the ID (see Dialog Options Name, ID, INFO, ObjectTree, Master in the manual „Introduction to CadnaA“) of objects. There are two types of groups:

User-defined Groups

  • User-defined groups: This requires to enter an „Expression“ as a pattern which - normally - refers a part of the ID of the associated objects.Example: The pattern „Road_*“ will include all roads into a group whose ID start by the string „Road_“. The rest of the string of these roads is not relevant (using the wildcard *). As a result, the roads having the IDs „Road_1“, „Road_20a“ and „Road_17present“ belong to this group, but not the road having the ID „Road17PLANNING“.

Software-generated Groups (ObjectTree)

  • Software-generated groups by defining a group in the ObjectTree (see ObjectTree). When using the ObjectTree, the group-specific pattern is created automatically by CadnaA based on the hierarchy level. When sorting objects into this hierarchy level (=group), the object ID will be preceded to the automatically generated pattern. Thus, all objects on a hierarchy level have a common pattern.Example: The ObjectTree shown below generates the patterns displayed in the Group table for each hierarchy level/group automatically:The string displayed on the „Expression“ column of the Groups table is automatically generated, depending on the hierarchy level. When assigning a CadnaA object to one of these groups, the respective pattern is put in front of the existing object-ID. This ID part is enclosed in exclamation marks (!). Since exclamation marks - among other symbols - are not allowed in manually defined IDs (see Dialog Options Name, ID, INFO, ObjectTree, Master in the manual „Introduction to CadnaA“) the software is able to distinguish this part from the rest of the ID. That is, this ID part represents the pattern of the group.

In general, using the ObjectTree when creating and managing groups is much more convenient to handle than user-defined groups. In particular, subsequent changes (e.g., moving objects from one group to another) are more safe in terms of data processing, since all the required groups can be defined in advance, i.e. before assigning the objects.

Principles for using ObjectTree groups

However, there are some principles to respect when using the ObjectTree in order to avoid unwanted changes to the ObjectTree‘s structure or even its destruction:

  • In general, ObjectTree groups should not be generated manually in the Groups table, but at the correct hierarchy level in the ObjectTree dialog (see ObjectTree).
  • Moving groups in the Groups table or sorting the table by a column should be avoided.

Note

Both points are not critical as long as only user-defined groups (i.e., without groups from the ObjectTree) are used. However, with ObjectTree groups, those must be listed at the top of the table, in the correct sequence and without duplicates. After, the user-defined groups get listed in any order.

  • In case the sequence of the ObjectTree-related groups in the Groups table is no longer correct, the tree structure in the ObjectTree dialog is broken and cannot be displayed correctly. As part of the consistency check, the group table is checked to detect such discrepancies and to display a message, if any.

Defining groups manually

Note

For group generation using the ObjectTree, see ObjectTree.

Whether an object is part of a manually defined group is determined by the string „Expression“ the Group dialog. When this pattern matches with the ID or parts of the ID of an object, this object is part of the group.

Wild cards may be used in the definition of the expression (see Searching for Strings CadnaA manual „Attributes, Variables and Keywords“).

Entering an expression

The source No. 1 has the following ID: Prod_102

The source No. 2 has the following ID: Prod_105

Group‘s Expression Effect
Prod* Both sources belong to this group.
Prod_??5 Only source 2 belongs to this group.
Prod_102|Prod_105 Source 1 and source 2 belong to this group.
*2 Only Source 1 belongs to this group.

With large projects, it is recommended to use the ObjectTree (see ObjectTree) for generation and management of groups, and not define groups manually.

Group Hierarchy and Partial Level

The groups are hierarchically structured. This is organized by the sequence of the groups in the table Groups. This list is checked top-down to decide about the activation status of an object. By activating or deactivating distinct groups, the activation status defined for subsequent subordinate groups have no relevance to the objects concerned.

Example for groups of sources in the Partial Levels table (Tables menu):

The sequence of the groups in the table has an effect on the calculation of the partial sum level per group shown in the table.

Note

Note that just those objects can get activated/deactivated by a group definition whose ID is switched to neutral („grey hook“, i.e. neither activated, nor deactivated) on the object‘s edit dialog (see Dialog Options Name, ID, INFO, ObjectTree, Master in the manual „Introduction to CadnaA“). Thus, for example, objects toggled active on their edit dialog cannot be deactivated by a group definition.

In the above example, six groups have been defined:

  • The first group contains all sources in the „Production“ group.
  • The second group contains Source 1, ID Prod_102, of „Production Hall 10“.
  • The third group contains Source 2, ID Prod_105, of “Production Hall 10“.
  • The fourth group contains the entire Hall 10 of „Production“.
  • The fifth group contains Hall 12 with the source ID Prod_123.
  • The sixth group contains Hall 13 with the source ID Prod_135.

None of the sources or groups were activated or deactivated during the calculation, but the „Do Nothing“ option was selected. This means that all groups and sources are considered in the calculation. Further, all partial sum levels per group are calculated at all active receiver points.

Now, by deactivating the first group „Production“ - containing all further sub-sources of all halls - none of these sub-groups would be considered in this calculation since those sub-groups are comprised in the top-group „Production“.

Even by activating all sub-groups - by entering a plus-sign + in column mark (M.) - would not have any effect. Thus, the sequence of the groups is important and decisive.

Now, change the „Expression“ of the third group to „Prod_??5“ and deactivate this group. This causes at once that the sixth group gets deactivated since the new expression (group pattern) applies to this group as well.

There is now way to re-activate this group unless it is shifted before the third group - i.e. in front of group with group pattern „Prod_??5“ - and activated explicitly. By activating this group - again by entering a + sign - all sources with matching IDs would be calculated.

Partial Level per Group

Clicking the „Partial Levels“ button on a Group dialog displays the A-weighted levels caused by all sources of a group at all active receivers.

Note

For frequency-dependent calculation results click the „Partial Levels“ button on a Receiver dialog (see Partial Levels).

The table header of the table Groups shows the abbreviation of each variant (see Variants), and below the active receivers and the partial levels for all evaluation parameters. Due to the limited space, spectra are not displayed in this table, but can be exported using a keyword (see Table in the manual „Attributes, Variables and Keywords“).

When maximum levels LmaxD/E/N (for industrial sources) are selected as evaluation parameters, the maximum level due to each source in the group (as A-weighted sum level, not spectral) at the selected receiver of the most recently calculated variant is displayed. Then, the result shown on the Receiver dialog is the loudest of these maximum levels.

Partial level at all active receivers

By contrast, the command Table|Partial Level displays the partial levels of all active sources at all active receivers for the current variant for the presently selected evaluation parameter.

With a maximum level LmaxD/E/N (for industrial sources) selected as evaluation parameter (see Evaluation Parameters Tab), the table displays at each active receiver and for each source for which a maximum emission level has been specified (see Common Input Data), the maximum level for the most recently calculated variant. Then, the result LmaxD/E/N displayed in the respective Receiver dialog is the loudest these maximum levels.