Analyzing and Resolving Over-Constrained or Inconsistent
Sketches
In evaluating geometry, the system considers the degree of
freedom that it has. In two dimensions, points and lines have two degrees of
freedom, circles have three and ellipses have five degrees of freedom. Fixed
geometry will never be moved by the system, and has no degree of freedom.
If all of the degrees of freedom of a geometry have been taken up by a
consistent combination of dimensions and fixed geometry, that geometry is said
to be iso-constrained (also known as well-defined). Geometry that still has
some degrees of freedom is said to be under-constrained (also known as
under-defined).
Status codes are given through a graphical way (colors) during the
Sketch edition. The update error dialog box when
returning in 3D explicitly gives them (check visualization of diagnosis in
Me > Preferences > App Preferences > 3D Modeling > 3D Modeling Core
> Sketcher > Colors.
Notes:
The system will mark all entities that are relevant to a problem
rather than just the first item encountered. So, for instance, in the case of
an inconsistent triangle with sides 10, 10 and 50, all three dimensions would
be marked as INCONSISTENT.
The order in which the codes are listed below is significant. The
system will test to see whether a geometry should have the status
over-constrained before considering whether it should be inconsistent.
Masks of these
colors also appear on the sketch features in the
tree
to indicate the constraint diagnosis of the respective
sketches.
This chapter describes the over-constrained and inconsistent status
codes calculated by the system and explains methods for solving any underlying
problems with a sketch.
