Dark Night Yogi:
Cool. was it the surrounding physical space or a 3d visualization in your mind?
It was the interior mental space that became unusually and spaciously three dimensional. This included the figure/ground arrangement of the candle afterimage/nimitta, plus the surrounding mental space, which became more like a realistically rendered landscape with vivid sense of depth, etc. Not sure about the observer function - it was fairly brief. Yes, I guess it was a bit like Avatar! Except with a better plot...
Thanks for feedback all. Paul