Hi okapi, I'm not really planning on hierarchies in styles - it will be Groups in MoI that I'm planning on having set up with parent/child nested hierarchies.

But I would like to add in something to "round trip" any existing layer hierarchy information that you had from the original Rhino file.

Unfortunately it is not very easy for me to do that right now, because I'm currently using the OpenNURBS v3 library for reading and writing 3DM files, and layer hierarchies were not added in until Rhino v4. Currently Rhino will not try to read the layer hierarchy information from a v3 3DM file which is what MoI currently writes out.

So I will need to switch to use the OpenNURBS v4 library to make that work properly. But I am pretty near the end of the MoI v2 beta cycle now, it is not really a good idea to make such a major change this late in the game.

So preserving the Rhino v4 hierarchies will need to be something that I can look into for MoI v3.

- Michael