Attach user data to custom grips polyline curve [C++]

Hello @dale and all,

I’m coding a custom grips object carrying a piece of custom user data, in C++ for the Rhino 5 SDK. For my sample, I have just taken your SampleCustomGrips example and added an instance of SampleObjectUserData to the rectangle created by the user.

Now, inside CRhinoRectangleGrips I have a pointer CSampleObjectUserData* m_user_data; which is initialized when creating the grips as just a copy of the user data originally attached to the rectangle (a point and a string).

Though, I have an error when retrieving the new rectangle with custom user data, the method CRhinoRectangleGrips::NewObject(). I attached my user data m_user_data to the polyline curve this way:

CRhinoObject* CRhinoRectangleGrips::NewObject()
  CRhinoRectangleUserDataObject* new_rectangle = 0;
  if( m_bGripsMoved && m_bDrawRectangle )
    CRhinoRectangleUserDataObject* pOwnerObject = RectangleObject();
    if( pOwnerObject )
      new_rectangle = new CRhinoRectangleUserDataObject( *pOwnerObject );
      new_rectangle = new CRhinoRectangleUserDataObject();

    ON_PolylineCurve pline( m_rectangle );
    ON_wString wStr;
    if ( 0 == pline.AttachUserData(m_user_data) ) 
	wStr.Format( L"Could NOT attach user data in CRhinoRectangleGrips::NewObject()\n" );
	RhinoApp().Print( wStr );
    new_rectangle->SetCurve( pline );
  return new_rectangle;

However, it doesn’t work. Could you please take a look? What would be a better way to attach the custom data?

The full project is here: (25.0 KB)

Many thanks,

Hi Pablo,

My apologies for not getting to this.

Perhaps I could use more information, in detail, as to what you are trying to do and why (in lieu if just typing up a sample). Can you give me more details?


– Dale