Quote - smooth can be achieved....such as in this Modo render

http://www.luxology.com/gallery/video/view.aspx?id=58

but at what cost, and for what purpose. I'd bet they used 100% straight raytrace for that.

 

I don't know how old that example is (or which version of modo it was done in) but it could have been a GI render, Modo has a render mode specifically for flicker-free walkthrough animations in which it only does GI calculation once, then re-uses that for all subsequent frames. It's obviously only useful when the camera is the only moving thing in the scene (if you move any lights or meshes you need a fresh GI calc) but it makes for very fast and flicker-free walkthrough renders.