Sketcher > Dimensioning Sketcher Geometry > About Dimensioning
  
About Dimensioning
Sketches are automatically constrained and dimensioned at every stage of sketch creation to keep the section solved. You can define new dimensions, modify automatically-generated dimensions, strengthen weak dimensions, and delete dimensions. You can dimension the following types of entities:
Geometry
Construction
Reference
Intent datums
Centerlines
 
* Although it is possible define a dimension between a centerline and another entity, you cannot dimension the length of a centerline.
Strong and Weak Dimensions
When you create an entity, weak dimensions are automatically generated. When you modify a weak dimension, it becomes a strong dimension. If you create another geometry, modify the geometry or other dimensions that relate to it, a weak dimensions may disappear. You can strengthen a weak dimension without changing its value. When you create a new dimension or strengthen a weak dimension, its value is rounded off if the sketcher_strngthn_to_def_dec_pl configuration option is set to Yes (default).
It is good practice to strengthen weak dimensions that you intend to keep in a section before you exit Sketcher.
Dimensioning Conflicts
If you strengthen or add a dimension that conflicts with an existing strong dimension or constraint, the conflicting dimensions are highlighted and the Resolve Sketch dialog box opens. To resolve the sketch, you must select one of the conflicting dimensions and click one of the following options:
Undo—Removes the selected dimension if you added it; weakens the selected dimension if you strengthened it
Delete—Deletes the selected dimension
Dim > Ref—Converts the selected dimension to a reference dimension
You can display an explanation of the selected constraint by clicking Explain in the Resolve Sketch dialog box.