Attaching Binary User Data to Objects

Raw binary user data on objects is available to plug-in developers through the object model as the UserDataBlob object. You can attach a user data blob to any object that supports the SceneItem.AddProperty method.

The UserDataBlob is similar to the UserDataMap, but supports storing object level binary data rather than per-component binary data. For example, if some user data is meant to apply to every point in a vertex cluster then it should be stored in a UserDataBlob, whereas, if the user data is meant to apply only to a single vertex, it should be stored at the correct index in a UserDataMap.

C++ Example: Applying a UserDataBlob to the scene root

// C++ example (using the C++ API) giving an overview of applying user data 
// to a scene object (the scene root)

	using namespace XSI;

	Application app ;
	Model root = app.GetActiveSceneRoot();

	UserDataBlob myBlob ;
	root.AddProperty( L"UserDataBlob", false, L"udb", myBlob ) ;

	// This is the structure that we would like to save inside Softimage
	struct ExampleData
	{
		double x ;
		int    y ;
		int    z ;
	} ;

	// Save the structure
	ExampleData data ;
	data.x = 90.1 ;
	data.y = 12 ;
	data.z = 14 ;

	myBlob.PutValue( (unsigned char*)&data, sizeof( ExampleData ) ) ;

	// Retrieve the structure again
	unsigned char * pBuffer = NULL ;
	unsigned int cntBuffer = 0 ;

	myBlob.GetValue( pBuffer, cntBuffer ) ;

	// We can conveniently read the contents of the user data
	// by casting back to the structure
	ExampleData * pData = (ExampleData*)pBuffer ;

	// Update our structure based on what is already on the userdatablob
	data.x = 3.15 + pData->x ;
	data.y = 12 + pData->y ;
	data.z = 0 ;

	// Save our updated values
	myBlob.PutValue( (unsigned char*)&data, sizeof( ExampleData ) ) ;