The following image demonstrates the TransparentWaterfall2DModel.

To use this model, assign a TransparentWaterfall2DModel instance to the WaterfallSeries2D.Model property.
System.Object
System.Windows.Threading.DispatcherObject
System.Windows.DependencyObject
System.Windows.Freezable
ChartDependencyObject
DevExpress.Xpf.Charts.PointModel
Waterfall2DModel
DevExpress.Xpf.Charts.PredefinedWaterfall2DModel
DevExpress.Xpf.Charts.SymmetricWaterfall2DModel
TransparentWaterfall2DModel