Blender 2.46 Instancing still needs a lot of improvement, but so far it is showing promising results.
If you notice in the screenshot I get an out of virtual memory alert, but I have 450 MB of physical RAM available, what happened I assume is that after loading the first round of geometry into physical ram, and than the rest into the virtual, blender rendered that geometry and emptied it from the physical ram, but than continued retrieving the rest from virtual ram, which is very very slow, it took 6 hours to render that image.
This was rendered with one sun light, nothing else:
I have managed to render up to 20 million polygons worth of instances before, the Peach team used instances to get to insane polygon amounts for the trees.
Of course I have 1.5 gigs of RAM so maybe you need more RAM.
That image contains 25 million verts, and 41 million faces, I have 750 MB of ram. I don’t think it matters how much ram you have because virtual memory can go well above the 2Gb limit, unless you made blender go above that.
Be warned that the instancing doesn’t work for raytracing - i.e. all faces will need to be stored in the octree. You should get better memory savings if you’re just using scanline features like shadow buffers.
