Not really a bug, just need to do your transform magic on the PRTs written from realfow Grid Domain.
Same issue as olden days, when loading a Grid Domain that was written in .prt format, the resulting .prt’s import into PRT loader transform upside down and backwards or similar.
For example the .bin of the Grid domain imports properly, the PRT of the Grid domain has whacky transform.
I spoke to the senior developer of RealFlow about it. I proposed to add a checkbox to flip the PRT into Max Z-up space.
In a future new version of the PRT file format, we hope to add metadata to provide the coordinate space, scale etc. so this can happen automatically on loading.
Another issue was that the body of the fluid was still saving a Density channel with a value of 0.0 and of course wouldn’t render.
I asked him to either write 1.0, or to disable the Density channel by default.
Not sure when this might happen since RF 2012 is already out I believe…
At this point, I would suggest using the BIN files and eventually resaving to PRT. We are pleased that both RF and Naiad are supporting PRT, but with all the coordinate systems out there (RF doesn’t even use the same system as Maya and Naiad) it is a mess.
Oh good so you guys already know…again 
Hows about posting a known issues thread, because I am just starting to assume that your guys already know about all the things I run into.
I am super happy that .bin works! I hadn’t seen anything in regards to Grid written .prts so thought I would speak up. I understand it is a mess too.
Don’t stop posting, the squeaky wheel gets the grease, it is good to know what people find and what is broken / annoying.
Sometimes if I complain internally about something, I need a proof that others are complaining too 
Naiad is also exporting in its own space, but there only a rotation of 90 about X fixed the problem.
With RealFlow, there is some scaling (flipping axes) going on too. Don’t remember the exact details, but I know Darcy posted in an old thread about it.
Time to go searching for it…
Will do
ATM it is certainly no big deal. Bin is just fine.
I just noticed I could export vorticity from a grid domain via prt. It is not currently possible without a workaround via writing out, reloading into bin loader, and recaching.
Pretty sure it was a mirror+some transform that I ran into a while back, it was a “What the heck is that” kinda thing. I remember spinning the thing around for 20 minutes trying to get it to line up before I saw what was going on.