Hi Michael ...

There is no perfect way, I suppose.

The advantage I see with Sketchup is that one can rotate the view considerably and still see the dimensions. It is possible, I think, to change the text size if it gets out of proportion. This is also true of Rhino, I believe.

With Rhino, changing the view point of a 3d object can skew the text so as to be unreadable.

For 3d details I now often simply set the perspective view I want and then annotate with some other software so the the dimensions and notes always face the reader. This is pretty awkward and time consuming but work better than Rhino's method.

I have not tried ViaCad yet so I don't know what the protocol is. I'll give that a try in the next day or so.

cheers,
eric