Hi all, I need some help with the ghost zone generation. Right now it's too slow, because it performs a cascading interpolation from the lowest levels to the highest levels, filling in available cells, then interpolating to the next level and repeating the process. Looking over the Enzo source code, I think we can do better: I think we should be able to replicate the Enzo logic much more closely, which only implicitly requires cascading interpolation, by checking parents and sibling grids. The issue of Subling grids I think we will also need to address. The current code is in AMRIntSmoothedCoveringGridBase. It's not that pretty. Does anybody have any ideas on whether or not we can do this better than it currently is done? Getting vertex centered data requires the ghost zones, and right now getting ghost zones is *easily* the most time consuming step of the volume rendering for many datasets. Dave, John, I know you've both dealt with this issue but if anybody has any ideas, they'd be greatly appreciated! -Matt