actually, this was not meant to lead to a rendered image at all. i experimented with particles in CGI, 10 per second, emitted in the center of the scene, about 10 cm from the objects you see in this rendering, blown into one direction by wind. i then applied so-called trails to connect them. what i actually wanted to get to, however, was a more loose connection of the particle objects by thin curves. it took me about an hour or two to find out how this can work. and while experimenting, this camera angle came up. the view was so beautiful, i introduced some light and did this high-res rendering with depth of field. the camera actually is in the particle stream, with the particles flying towards us, and it looks into a world of macroscopic dimensions. that‘s why the DOF is so shallow, even with a pretty small aperture.