Choose Elements

For each element type that you want to report on in the attribute file you must include a block of commands in the configuration file. This block starts with the type of the element, and ends with the corresponding END_ command. Between these two you include the attributes that you require.

For example:

BRANCH

ALL_ATTRIBUTES

ALL_UDAS

END_BRANCH

VALVE

NAME

SPREF

:MANUFACTURER

END_VALVE

Each element found when ExPLANT-I is scanning the Design database according to the export commands is checked so see if it is one of those listed in the configuration file. If it matches, a MicroStation Cell is added to the dgn file. Since the Design is hierarchical, with, for example ZONEs containing PIPEs containing BRANCHes containing VALVEs, this will, by default create Cells within Cells in the dgn file. This can lead to two problems:

• There is a limit on the amount of data that can be put in a MicroStation Cell. A ZONE will almost certainly exceed this limit.

• Some applications that read dgn files may not interpret nested cells correctly.

To deal with these situations it is possible to tell ExPLANT-I to handle some elements differently, and either to use an empty cell, or a cell containing geometry, but not nested cells. If you use the EMPTY qualifier on an element line, for example

ZONE EMPTY

NAME

END_ZONE

ExPLANT-I will create an almost empty cell in the dgn file, and link the attributes to that. As the cell is almost empty it will not exceed the size limit. The cell will not be completely empty as many dgn file readers reject completely empty cells. (If necessary, a line of zero length is put in the cell). It will often be better to use the facilities to report on the attributes of another element (described in the topic, Attributes of Other Elements) to report attributes of these very high-level attributes.

If you use the NONEST qualifier on an element line then ExPLANT-I will write a cell to the dgn file which may contain geometry, but will not contain the cells of other elements from the configuration file (it may contain cells produced for geometry defined in Marine as facets). It is recommend that you only use this option if the system reading the dgn file cannot cope with the default NEST option.

An example of a possible use of NONEST is when you want to have cells for valves, but to gather all the geometry within a branch except for the valves into a branch-cell. You can express this as:

BRANCH NONEST

ALL_ATTRIBUTES

END_BRANCH

VALVE

ALL_ATTRIBUTES

NAME OF BRANCH

END_VALVE

If a particular cell would exceed the maximum possible size, ExPLANT-I will exclude some of its contents from the cell. All the geometry will be included in the file, but it will not be included in the cell structure. If this happens, a warning message is output to the log-file.