I just ran into the same problem! The model is drawn to 0.001" precision but there's no matching precision in layout. I can't simply convert to metric because Layout's mm precision is limited to 0.1mm. sigh
I did post a reply on the Layout wish list; so, hopefully that will help get it fixed.
regarding the topic of dimensioning & SketchUp for engineering, I thought producing a dimensioned and annotated 3D PDF would be a great & simple way to pass the model along to collaborators and contract manufacturers π
unfortunately, it seems the current 3D PDF export pluggins don't work so well for this:
The SimLab 2.4 pluggin exports only 2D plane 3D geometry; it does NOT export points, lines, guides, text, nor dimension entities - which makes it practically impossible to create a fully commented/annotated 3D model in PDF. π
However, with Adobe Acrobat, you can enable the 3D PDF for analysis & measurement within the free Acrobat Reader which is pretty cool. ...but measuring is still a pain compared to having the dimensions already called out...