Autodesk Developer Network 2011
Autodesk
Updates on Rebar API
§Big changes in rebar shape related APIs
§Steps to create rebar shape
§Methods to create/edit rebar shape
§ElementId of shared parameter must be the argument throughout rebar shape definition methods
§Main work of migration
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§Minor changes
§Element creation APIs are moved to its representing class
§Document.Create.NewRebarHookType  à RebarHookType.Create
§Document.Create.NewRebar àRebar.CreateFromCurves & Rebar.CreateFromRebarShape
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The APIs to create and edit rebar shape have undergone considerable changes.

First change is the steps to create Rebar shape
In 2011, the steps were:
Create a RebarShape inside the Document.
Create a RebarShapeDefinition inside the RebarShape.
Add data to the RebarShapeDefinition.
Commit the RebarShape.
In 2012, the steps are:
Create a RebarShapeDefinition. (It refers to the Document, but is not inside the document.)
Add data to the RebarShapeDefinition.
Create a RebarShape inside the Document based on the RebarShapeDefinition. (Only now is the document modified.)

The second changes are the  changes of methods.
the following methods are removed:
Autodesk.Revit.Creation.Document.NewRebarShape()
RebarShape.NewDefinitionBySegments()
RebarShape.NewDefinitionByArc()
and replaced by:
RebarShape.Create(Document, RebarShapeDefinition, ... )
The RebarShapeDefinitionBySegments constructor.
The RebarShapeDefinitionByArc constructors.

In Revit 2011, Shared parameter is used in the methods to define the rebar definition shape. Now ElementId of the shared parameter is used in those methods. RebarShapeParameters class provides method to obtain ElementId the corresponding shared parameter.

Because of these big changes, the main work of RST plug-ins is for rebar shape creation. The code have to be updated according to these changes. For anything about the code migration, please Search the What’s New section in RevitAPI.chm file. It explains the reason.

The minor changes related rebar are the method to create the rebar hook type is a static method RebarHookType class, and the method is renamed to Create. Overloaded methods to create rebar are moved to be static  member methods of Rebar class and we now have exclusive methods called CreateFromCurves and CreateFromRebarShape to create new rebars. They no longer return null for invalid arguments, and they no longer regenerate the document.