Say I have a line and an arc. I want the line's length controlled by the arc's length. But, the arc is a hidden, not visible, object. So when the line is selected I want the grips for the arc to be displayed, and dragable, along with the line's grips. However, I do not want the implied selection set to be modified by just adding the arc to it. Is this even possible?
What I'm actually working with are an arc and a Civil3D curve label for that arc. It's the arc I want to be not visible, but it needs to be available for editing when the label is selected. I thought the line/arc would be simpler to explain... I have tried using the ImpledSelectionChanged event, checking for the Xdata I've added to the label, and adding the arc to the ImpliedSelectionSet if such a label is found. This actually works as I had hoped, except it breaks the normal C3D editing of labels which are in an ImpliedSelectionSet.
I've also tried to get the arc grip points and add those to the Label Grip points. This, so far, has resulted in lots of Fatal Errors so I changed it to the ImpliedSelectionChanged option. I would rather get this working, but am out of ideas. If I could get an example for the line/arc scenario, I'm sure I could adapt it for use with the label/arc.