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## Typical Applications

There is a number of applications which are particularly suitable for the use of constructional relations. One of these applications has already been shown examplarily. Below please find another typical example.
The main range of application for constructional relations are form variants, i.e. one or more geometrical objects, comprised in groups, appear with different frequency in the different variants.
Example (form variant - plate with borings): A plate with borings shall be constructed. The number of borings shall be dependent on the length of the plate (the longer the plate, the more borings).
First a rectangle (base line G1) is created and a boring K1 is positioned with the desired distance to the edges.

Figure 3: Form variant - plate with borings

With the help of the command

COPY CIRCLE LIN OP=<k1>;LIN=<g1>;DST=30;CNT=TRUNC(LENLIN(<g1>)-30)/30;SAVREL=1!
in this rectangle the boring is copied along the base line CNT-times with distance=30. The number CNT is defined with a formula so that the borings always have the same distance to each other over the length of the plate.
Constructional relations are saved.

Figure 4: Form variant - plate with copied borings

If the length of the line G1 is modified (e.g. by moving the right side of the plate with a value DY=60), the result is the corresponding plate with an adapted number of borings, in our case 6 borings.

Figure 5: Form variant - plate with adapted number of borings

The number of borings will always be in relation to the length of the line G1 as defined by the user.