Each geometrical object is defined by its parameters, a point for example, by
its 2D co-ordinates. The degree of freedom of a geometrical object is a
parameter of the object that can be manipulated freely.
In SISCAD-P the individual geometrical objects can be defined with the
following degrees of freedom:
As described under Constraints within SISCAD-P, the constraints do not totally restrict geometrical objects but partially. So it is possible that an object which has some constraints may also have some degrees of freedom.
Depending on the number of degrees of freedom of a geometrical object the following terminology is used:
The sum of the degrees of freedom of all geometrical objects of one part
is the number of the degrees of freedom of this part. A part is
underdetermined, when there are some degrees of freedom left and
exactly determined, when there are no degrees of freedom left.
The number of the degrees of freedom is a decisive criterion to see how
SISCAD-P behaves in parametric drawings when a manipulation is made.
If an object has no degrees of freedom left, SISCAD-P will not change this
object for example after modifications of the dimensioning, which do not
directly concern this object. If an object has some degrees of freedom left,
SISCAD-P is free for modifications of the dimensioning and the object can
be manipulated, if necessary.