This is a preview of real time Image Based Lighting (IBL) in the pre-alpha version of Tachyon Render. Use a HDR environment map to light your scene quickly with little performance penalty.
Changing the high dynamic range (HDR) environment map allows to change the light mood quickly without the need for a different light setup. The impact on render times is minimal. The image based lighting fills in shadows nicely and results in a much richer lighting.
See some examples of the same scene with different HDR environments below.