Description Key Parameter Substitution

There are two key components to Description Keys: The “Code” and the “Format.”

You take a shot in the field, and you add a description to the shot. That description is know as the “raw description.” The points are dumped from the data collector into Civil 3D, and filtered through the Figure Prefix Database, and Description Keys. The “Code” in a description key is compared to the “raw description” you entered, and the Format is the translation tool that yields the “full description” Civil 3D places in the drawing. The lifecycle of a points description is from raw data, through code, to format, to full description. Civil 3D can list this information for you all at the same time to avoid any confusion.

For example, if both your raw description and code for a building is “11″ or “BLDG,” then your “Format,” or “full description,” might be BUILDING. However, notes often accompany raw descriptions. For example, it would be common to describe a building as “BRICK.” Therefore, if the raw description is BLDG BRICK, the description key code could be BLDG* and the format could be BUILDING $1.

The $ (dollar sign) above is a description key parameter. When a raw description is entered into a data collector, each series of characters separated by a space (it is highly recommended you use a space, and not a dash) takes on a unique variable. The variables can range from $0 to $9 and $0 is always the first series of characters. If a raw description is BLDG BRICK and the format is $1 BUILDING, Civil 3D will fully describe the shot as BRICK BUILDING in the drawing. If the raw description were something like “TRE OAK 24,” you could enter a code of “TRE*” and a format of “$2″ $1 TREE” to yield “24″ OAK TREE” in a drawing.

Other parameters include:
$+ Reference all the parameters in the raw description after the leading element. Use this instead of BLDG $1 $2 $3, etc.
$* Reference all the parameters in the raw description and also the leading element.
$$ Insert a single $ into the description. If you used $$200.00 as part of the format, then that part of the translated full description would be $200.00.
$* Use the point’s raw description for the full description. If you used the raw descriptions UP-1, UP-2, and UP-3, and you want to use these descriptions for the full description, then use the $* as the format.

Codes and parameters are powerful tools in Civil 3D, but be careful: If you use numerical descriptions, the code 11* would yield the same results as 114, 115, 1129, 118, etc. If you use the code BR* with a format of $+, a point with a raw description of BRICK or BRIDGE would yield the same results – the same full description.

Click on the following links for a free 2-part series in configuring Code Sets, Description Keys, Figure Prefixes, as well as point object and point label styles in Civil 3D 2010.

Configuring AutoCAD Civil 3D for Land Surveying Part 1 of 2
Configuring AutoCAD Civil 3D for Land Surveying Part 2 of 2

Civil 3D Library
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