There seems to be a bug in RhinoDoc.BeforeTransformObjects event, when raised you receive in args the number of the objects transformed, but the RhinoObject array is always null:

int e.ObjectCount = n -> (1,2,3…)
RhinoObject[] e.ObjectCount = null

Here a screenshot:

Best Regards

During BeforeTransformEvent, how can I find selected objects when modifying curves by transforming control points?
(Steve Baer) #2

Thanks, I added this to our bug tracking system at
and will try to take a look at it soon

(Steve Baer) #3

I see the bug and just fixed it a few minutes ago. This may not show up in the WIP until next week. Thanks for the report


Thanks for let me know.

Kind Regards.

(Matthieu Arnold) #5

Good afternoon Steve
I’ve got the same issue, is it supposed to be fixed also for Rhino 5?
I tried to update the sdk but all the same…

Here is my code:

’ RhinoDoc.BeforeTransformObjects event handler

    Public Shared Sub OnTransformRhinoObjects(sender As Object, e As DocObjects.RhinoTransformObjectsEventArgs)
        RhinoApp.WriteLine("** EVENT: Transform Objects **")
        RhinoApp.WriteLine(e.ObjectCount & " objects will be transformed")
        RhinoApp.WriteLine("Transformation:" & e.Transform.ToString)
        For Each tp In e.Objects
    End Sub

Best Regards

(Steve Baer) #6

Hi Matthieu,
This was most likely not changed in Rhino 5. Have you tried this in the V6 WIP?

(Matthieu Arnold) #7

No, but my end user has Rhino 5, so I wish to stay with this one.

I’m trying to use the RhinoDoc.SelectObjects event instead to redraw my custom objects, but as it is raised very frequently I fear to slow down Rhino.

(Steve Baer) #8

We typically almost never have to use an event watcher for any sort of custom geometry drawing. If you are using a display conduit, you will get called for drawing at the appropriate time.