I was wondering if this is just how it is or there may be ponteially a fix for this. I currently have 12 forest pack items in my scene, all vegetation, i find that the interactive render starts much slower when i have them all turned on. When i turn off the layer with all my forest vegetation, its so much quicker - is there a reason for this apart from the calculation of so many items? or perhaps it could be something else? ie like opacity maps or something? any optimisation tips just in case?