Sometimes lighting the scene from HDRI image only is not enough. We get blueish shade and shadows are not that crispy we would like to have.
In other rendering engines we can add mr Physical Sky to environment, to get more sharp light.
As you know using HDRI image together with mr Physical Sky in iRay wasn't possible.
Well, until now...
As many users of 3ds Max iRay had time to figure out, the use of mr Physical Sky in iRay is slightly different from that to which we are accustomed to using Mental Ray.
These differences are painfull especially when you want to separate control the colour of sun and sky in iRay.