/// <summary>
/// Remove a previously added interaction
/// </summary>
/// <param name="i">interaction to remove</param>
public void RemoveInteraction(Interaction i)
{
interactions.Remove(i);
}
/// <summary>
/// Adds a specific interaction to the PlotSurface2D
/// </summary>
/// <param name="i">the interaction to add.</param>
public void AddInteraction(Interaction i)
{
interactions.Add(i);
}