1. FAST6191
    The basic nsbmd viewer used by many DS ROM hackers, it falls short on some of the newer variations (lowline's console tool, tinke and MKDS course modifier as well as NSBTXExtractor make up for a lot) but it a key part of any rom hacking toolkit aiming to do work in 3d (most games use the NSBMD format if they use 3d).

    Specifications
    http://sites.google.com/site/kiwids/nsbmd.html
    Newer/more accurate specifications
    http://llref.emutalk.net/docs/

    Usage
    nsbmd is an utility to dump the contents of *.nsbmd *.nsbtx files.

    usage: nsbmd [options] filename.nsbmd
    options:
    -d --dump dump the content of file only.
    -c --code dump also the code for mapping.
    -t --texture extract the textures, if any.
    -v --vertex dump also the vertex of polygons.

    If using the 3d viewer usage there is as follows
    - Hold left mouse button to rotate
    - Hold right mouse button to zoom
    - T toggles texturing
    - C toggles vertex colours
    - W toggles wireframe
    - B toggles backface culling
    - F toggles texture filtering
    - P toggles polygon mode