My main goal was to extract the XDR files or .RSC85 (found the tag for the terrain_tile files) to export the terrain with working uv mapping to import into gta 5 as openiv progresses on that front.
Since the xdr format should be really analog to any model format minus the specific rage types. Vertices, faces , normals uv's etc.....
If you want some help pm me.
There are no #dr resources "as is" in RDR.
Model-related things are stored in #vd (xvd, cvd), #ft (xft, cft), and other resources...
From the beginning it is better to start from #vd because this is the most understandable format.
I am not experienced a lot in 3d model research, so glad to see that someone is interested in the RDR file formats.
Hope when reditec finishes RPF extraction and edition, it will be fine to start community research of resources.
p.s. There are RSC 85/86 and 05/06 containers.
05/06 are the same as in GTA IV and Midnight Club, but 85/86 is a bit different (two flag fields).