I'd just like to add my voice to those calling for a better 'organisational / grouping / layering system'. Yes, I'm deliberately being rather vague with the terms there : ) Given it's now 64 bit status MOI is much more capable of managing larger datasets - and those bigger models and assemblies require more powerful organisation tools. As a relatively new user, but a long time 3D generalist, I feel 'object management' is one of the areas I'd really like to see improved.