With the release of LuxRender 0.8 comes a new competition. The competition has been running since early this month, and ends at the end (strangely enough!). The example previous competition was a to luxrender example scene that could ship with the installer. I didnt enter this one due to time constraints.
However I did enter the Simple is Beautiful competition. Long ago I attended a conference and during the tea/coffee bio break session there was a technology stand, it was quite striking and showed what appeared to be the fuel/control rods at the top of a reactor, surrounded in a bath of Cherenkov blue haze. It was very pretty, and since then i thought about making something similar in Lux.
However, back then to achieve such and effect was possible, however it was somewhat limited and involved using the Bound Volume interface, I never got it to work in a satisfactory way. With the advent of homogeneous volumes in lux, it became possible to do this far more easily, and quickly.
I cannot go into alot of detail, as the scene is infact very simple. It consists of a long tube, which is filled with smaller tubes of a similar length. The inner tubes are smaller and are supposed to represent the control/fuel rods. I then used the homogeneous volume settings to set the atmosphere to absorb and give me a blue haze, and the scattering value to something small, but large enough to give me a desired brightness for my ‘god rays’.
Physically this isn’t really correct, as the Cherenkov is an emission rather than a scattering, and the blue colour isnt from the absorption at all… however, to fake the effect I was after, for this scene it is ok.
The part which really gives the cross lighting effect in my scene is that the lighting is a disc placed at the bottom of the larger tube, it is small and only really covers the inner 4 tubes, hence any other light that is seen is an effect of scattering or multiple bounces around the scene.
The scene was rendered for about 1 week on 6 CPUs and here is the result.