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## Dimensioning Concept

The standard task of dimensioning is to change a CAD construction into a manufacturing drawing. In parametric systems the dimensioning also adopts the function of controlling geometry with its dimension values. To make these two completely different applications as clear as possible for the user, SISCAD-P offers two different kinds of dimensions.
The first usual method of dimensioning, the values of which automatically adapt during geometric modifications, is called reference dimensioning. This dimensioning references the current geometrical state.
The second method of dimensioning takes over the control of the geometry during parametric working and is called parametric dimensioning. Here the dimension value determines the circumstances, i.e. the geometry automatically adapts to the modification of a dimension value.
These two kinds of dimensioning are designated with different colors, defaults are yellow = parametric dimension , green = reference dimension .
It is selfevident that the WYSIWYG principle is also valid during the creation. As soon as you have identified the objects to dimension, you can place the dimension at the desired position. The input of other parameters (modification index and other) is immediately taken into consideration in the dimension figure.
For the determination of the dimension image the user has several possibilities. The conformity to DIN (German national standard) rules is one of the most important features, however user-specific adaptations are possible.
For the modification of a dimension value of a parametric dimension the command MODIFY NOMINALSIZE is relevant. After the modification of a dimension value the geometry is modified in accordance with the construction logic. This logic is determined by the user during construction. The parametric concept of SISCAD-P provides the suitable tools for this purpose.