Model-Based Definition > Model-Based Definition > Creating Various Annotation Types > Dimension Properties > Ordinate Dimensions > About Ordinate Dimensions
  
About Ordinate Dimensions
Ordinate dimension Annotation Elements and model ordinate dimension annotations use a single witness line and are associated with a baseline reference. Note the following points about ordinate dimensions.
You can create ordinate driven dimensions in 3D models as model annotations or as Annotation Elements. You must first define an ordinate baseline Annotation Element, and then define model ordinate dimension annotations and ordinate dimension Annotation Elements that reference the ordinate baseline Annotation Element.
Multiple ordinate dimension annotations and ordinate dimension Annotation Elements can reference the same ordinate baseline Annotation Element. Such annotations and Annotation Elements can belong to one or more annotation Features.
All ordinate dimension annotations and ordinate dimension Annotation Elements use the annotation plane of the baseline Annotation Element they reference. To change the orientation of an ordinate dimension group, you must change the orientation of the baseline.
You can select geometry such as a surface, linear entity, point, datum (datum plane or datum axis) or coordinate system as the reference for an ordinate baseline Annotation Element. You can also select an intent object, that is, a surface, linear entity, point, or coordinate system.
When creating a new ordinate dimension, you can choose to select an existing baseline annotation element or create a new one. If you create a new baseline Annotation Element, Creo Parametric creates a new baseline Annotation Element in the same Annotation feature as the ordinate dimension Annotation Element being created. When creating a standalone ordinate dimension annotation, Creo Parametric creates a new Annotation feature with an ordinate baseline Annotation Element.
If you choose to use an existing baseline to create a new ordinate dimension, you can select an existing ordinate baseline Annotation Element, or the geometry that it references or the ordinate dimension (either model or Annotation Element).