After a lot of hard work from Matt and Jeff, yt now has the capability to generate multivariate volume renderings. Lately Matt added Rayleigh scattering to the ray tracer, which produces superb results in some of these renderings. I just wanted to showcase a couple of renderings to show what's possible with it.
Reionization simulation at redshift 8.5 in a 12.5 Mpc/h box with 512^3 resolution, unigrid. 10^6 solar mass dark matter resolution.
Dwarf galaxies forming in a pre-heated medium at redshift 17. The clouds are on the order of 10^7 solar masses. The simulation considers radiative feedback from Pop III stars and their remnant black holes.