We really want to get some nice god rays into the game as it completely makes the style of game we're after and Unity make it rather difficult at the moment. The options i've researched are particle effects, and geometry (the pro version of unity has "sun shafts" which are great if your camera is looking near the light source but otherwise useless).
I had a look at a third party particle system which gave great results (P-system A) but was excessively machine heavy
Using the unity particles is a great middle ground as the system impact is almost null.
Looking at geometry with an alpha was an option but in comparison to particle effects it has a very dated appearance without some serious shader work.
The highlighted options in the profiler (unity utility) show the massive difference between the third party and unity particle system.
In our scene instead of isolation the third party dropped the run fps down from 100 to 35 in some places, there was little control over the spacing as if i duplicated the particle system it would destroy the frame rate further. In our scene with the unity standard particle system the frame rate was practically unaffected, sitting at 100 - 120 fps comfortably.
