I'm new to strata and have been using it for about a month now for fairly simple purposes. I have an animation i want to render which is 360frames at 30fps. I have done a few movies of this model and sometimes rendering this short movie takes ages (72 hours plus) other times it only takes 3hrs. The quality is not particularly high, and in each of the renders the same settings have been used. What seems to take ages is the casting of the photons, the rendering of each frame itself takes a few minutes. As each frame progresses it takes longer and longer to cast the photos and i have no idea why?