# Ripples

In this example, we place a circular ripple in the image (as if a rock or something had just hit the water). We specify that there will be one disturbance on the ocean, a ripple. Note that the `render_disturbances` parameter has no effect for a ripple. The ripple will be centered at x=0, y=0 relative to the origin of the ocean. Additional input information about the ripple is in the file `ripple.dat`. Since this is a relatively large ripple, we choose a resolution of 0.5 meters. For smaller ripples, you would want a smaller number here. The values for `dx` and `dy` here as well as `dx` in the ripple file should all be same. In the `ripple.dat` file itself, we set the starting time for the ripple at minus five seconds, so that our first frame at time zero will be five seconds into the ripple. The ripple has a radius of 4 meters. Since the ripple obviously grows with time, this is just the initial size. The `v_o` parameter controls the direction and speed of the water in the center of the ripple at the instant that the ripple starts. In this case, the water in center of the ripple is moving upward at 10 meters per second in the first moments of the ripple. This number may be either positive or negative.

``

           RenderWorld_data_file ocean 5 5
           n_points_x 1024 1
           n_points_y 1024 1
           dx 0.1
           dy 0.1
           spectrum_file spec2.dat
           generate_file yes
           random_seed 91401
           end
           number_aux_oceans 0
           number_disturbances 1
           render_disturbance  black
           grid_type ripple
           n_points 1000
           not_used 1
           dx 0.5
           dy 0.5
           file spectra_rip.dat
           generate_file yes
           file: ripple.dat
           centerPoint_x 0
           centerPoint_y 0
           end
           box_depth 20.
           reference_time 0
           surface_type round
           radius 6371230
           max_distance 100
           double_distance 60
           wind_type fixed
           wind_direction 90
           wind_velocity 8
           waves yes
           water_type 3
           external_exact no
           glitter yes
           whitecaps no
           textures no
           sunbeams no
           exclude_items no
           number_of_bands 3
           band_ids 1 2 3
           index_of_refraction 1.34 1.34 1.34
           end

The ripple file `ripple.dat` is shown below.

    reference_time -5.
           radius 4.0
           v_o 10.0
           n_points 1000
           dx 0.5

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