  We present a light and fast, public available, ray-tracer {\tt Splotch}
software tool which supports the effective visualization of cosmological
simulations data. We describe the algorithm it relies on, which is designed in
order to deal with point-like data, optimizing the ray-tracing calculation by
ordering the particles as a function of their ``depth'' defined as a function
of one of the coordinates or other associated parameter. Realistic
three-dimensional impressions are reached through a composition of the final
color in each pixel properly calculating emission and absorption of individual
volume elements. We describe several scientific as well as public applications
realized with {\tt Splotch}. We emphasize how different datasets and
configurations lead to remarkable different results in terms of the images and
animations. A few of these results are available online.
