The Spreadsheet command (from Tools Spreadsheet) enables the user to create equations that control the relationship between a new dimension and other dimensions, or between the new dimension and a non-dimension variable.
An example of this is that of a Slot feature where the size of the slot is dependant upon the overall length of the base of the profile. Thus, a variable for the base can be named "BASE" (note that variable names are case sensitive and cannot contain spaces - use a dash or underscore for spaces). Dependant variable names can be given for the dimensions driving the slot shape as "SLOT_LFT" and "SLOT_RGT".