To create this ripple effect I used the following workflow. First, I created a square grid of points whose size and spacing can be adjusted with sliders. I then created a list of points that corresponded to the start points for the cylinders with zero height. Next I created the adjustable point which demarks the pebble. Using the distance from the pebble point to the cylinder points, I created a sine wave function that includes an amplification factor, base offset, and dampening value. I then used the Geometry.Translate function in order to input the sine wave heights into the geometry values from the cylinder start points. Finally, the new set of points from Geometry.Translate was fed into the family instances to create the Revit family model.