For many years people have been creating drawings using Autodesk AutoCAD. Some drawings are simple, some are more complicated. But none the less, these drawings are constantly being modified or added on to them. And unless you turn off layers, or use the Isolate option, parts of the drawing not intended for modification, are vulnerable to being accidentally modified. Where even a minor adjustment of the position of a line can make a drawing inaccurate; or in other words, wrong.
Recently added to AutoCAD are Constraints. There are both Geometric and Dimensional Constraints, as seen on the Parametric tab on the Ribbon.
These constraints make a drawing parametric. A parametric drawing has constraints in its geometry to ensure that the design meets specified requirements. However, just because a drawing has constraints, it doesn’t mean they are the right constraints.
One of the biggest issues to consider when adding any constraint, is the intent in the constraint. And it’s best to go all the way to the source. So just by intending two lines to be parallel with each other, is not the full intent of adding a constraint that places them parallel. You also need to investigate if either line is already constrained to any other geometry. And if so, you need to consider if that geometry is modified, how will it affect these lines. Perhaps you don’t even want them to be affected at all. Maybe you only want one of them to be affected.
Another issue to consider is leaving geometry only partially constrained, or constrained to other geometry that has no other constraints; in other words, leaving geometry not fully constrained. By leaving geometry only partially constrained, means it is still vulnerable to an accidental change.
Before you add any constraints, you should verify first if they have any constraints assigned to them, and if so, which ones. When you hover the mouse over geometry that has constraints, an icon symbol appears, as shown.
To display which constraints exist, use the Show/Hide commands on the Parametric tab. Constraint symbols will appear near their respective geometry as shown.
It’s good to be creative in your design, but sometimes you need constraints to hold those ideas solid. So be sure to add constraints, even if at first they aren’t the right constraints, because as the design unfolds, you’ll be better prepared to make the right adjustments.
“To live a creative life, we must lose our fear of being wrong.” – Joseph Chilton Pearce