For future reference.
On Ubuntu 18.04 g++9
povray bogus.pov Radiosity_File_Name="RadSamples" +rfo +rfi
coredumps unless the RadSamples file exists. The file can be empty
and things are fine but it must exist. We certainly should not
crash, and in my view given how +rfo always appends to any existing
file, the user should not have to change the rfi flag use based on
whether the file exists or not.
Bill P.
