Rules for Working with External Variables

An expression of an external variable can only be a constant. The variable is marked as external in the variable editor using <Ctrl><D>. However, if the variable is not set as a constant, it will not be marked as external. Usually all other variables depend on external variables. The dependency is defined by the formulas that you enter in the Expression column. When you change the values of external variables, the values of the other variables are calculated, and the drawing changes after you exit the Variable Editor.

External variables are the main link between the T-FLEX CAD system and other systems and applications. You can write external variables to an ASCII file in the Save parameters command and in the variable editor using <Ctrl><W>, read them from the ASCI file in the Load parameterscommand and in the variable editor using <Ctrl><R>.

External variables also serve to organize a parametric relationship between the main drawing and parametric fragment drawings.

External variables for fragment drawings are written to the Assembly Drawing structure file in the Report command and are read when the assembly drawing is automatically generated from fragments.

When creating new variables as parameters of certain graphical elements of the system, you can visit these variables as external ones.

To edit external variables, use the External Variables command. You can assign editing tools for external variables.

To do this, in the Set Document Parameters command, under the External Variables tab, select one of the following parameters:

•internal editor (called the t-FLEX CAD variable editor).

•external program (the user-specified software tool is called).

•control (calls control dialogs created by the user on the specified drawing pages).