Hi,
the situation is still the one described e.g. at Read 2-dimensional c-array branch with RDataFrame and Does RDataFrame support tree branches with 2d arrays? .
TL;DR: RDataFrame does not properly support multi-dimensional C-style arrays because TTreeReader (which RDF uses internally) does not. The relevant JIRA ticket is [ROOT-9509] [DF] Add proper support for multidimensional arrays - SFTJIRA . For arrays with static size, you should be able to read them as uni-dimensional arrays (i.e. flattened), while multi-dimensional arrays with one dynamic dimension as far as I know there is no workaround at the moment (as per RDF issue with CMS MiniAOD branch ).
cc: @Axel
Cheers,
Enrico