The Revit API is built into every copy of Revit and enables you to:
- Access all elements in the building information model
- Query element properties
- Change element properties
- Perform additions of elements – with the types of elements that can be programmatically added expanding with each new Revit release
- Managed assemblies to work with Revit API (i.e., RevitAPI.dll and RevitAPIUI.dll) are present in every Revit installation under \Program.
The SDK is included in every Revit product. There are two ways to install the Revit SDK :
- From the main page of the Revit installer, click “Install Tools and Utilities” and choose “Revit Software Development Kit”.
- Alternatively, you can also find the SDK in the extraction folder, under:
- <extraction folder>\support\SDK\RevitSDK.exe
You can also download the updated Revit SDK from the Autodesk Developer Center.
Credit: Luke Johnson's What Revit Wants blog.