Error when applying PreDrawObjects

Hi guys,

While trying to add lines in PreDrawObjects of conduit class I have noticed that some lines are missing when you try to rotate the view.

When declaring the conduit - I am joining all the bounding boxes of the lines into one bounding box (m_bbox) which is used later in the following sub:

Protected Overrides Sub CalculateBoundingBox(e As Rhino.Display.CalculateBoundingBoxEventArgs)
      MyBase.CalculateBoundingBox(e)
      e.BoundingBox.Union(m_bbox)
End Sub

So, what can be the problem?

Thanks in advance!

Kind regards,
Dmitriy

It seems that i fixed the problem by using IncludeBoundingBox method.
However would like to know what is the difference between IncludeBoundingBox and Union methods.

Thanks,
Dmitriy

The problem with Union is that it is working on a value class and therefore that value is not getting set back on the eventargs

Thanks, David

Now it is clear.