The plugin was based on a technique called Optical Stacking. In the early days of 3D Seismic Interpretations, Seismic Sections were printed on glass sheets or glass panes and then stacked on top of each other. On viewing along the a particular direction, the Faults would appear darker, since along that direction the reflection amplitudes would reinforce each other. This was the simpe idea I used in my plugin to improve visualization of such linear features in 3D Seismic Cubes, which would in turn aid Seismic Interpretation.
So my plugin for Petrel allows visualizing many structural and stratigraphical features such as FlatSpots, Faults, Pinch-outs, River Channels, Horizons etc. and it had an interactive method for defining the direction of stacking in the 3D window itself.
P.S. I am not open sourcing the source code of my plugin, but if you are interested, feel free to drop me a mail.
Here are some of the results generated by this plugin: