From:  OSTexo

I'm guessing that the hidden line removal in MoI will be more elegant, but I found a decent workaround using Rhino that will work until MoI has the feature. I ran into a similar cost justification problem, but in my case it had to do with technical illustration not being my primary job. I am using Rhino v5 Beta to do this and am not sure if this is present in Rhino v4. I design the model in MoI, position the items how I like, and open the 3DM in Rhino. I then select isometric view in Rhino. I run the Make2D command, make sure I check show tangent lines and uncheck show hidden lines. I then select Top View and examine the result. It is not perfect 100% of the time, sometimes the curves aren't watertight so I use Trim, Join and curve blending tools in Rhino to fill in any gaps or to tighten up the lines. I export to AI and it opens up just fine in Illustrator, where I can work on it some more if I like.