Thanks @sketch3d_de for referring to my post there and the constructive contributions you made to it. I posted it at the time coming from a professional exposure as architect in Switzerland and Germany where specific dimensioning standards are strictly applied and unfortunately not supported by SketchUp Pro/Layout, and because I think a number of users may face comparable difficulties in various countries and industry areas.
I saw in-between a number of other related posts, this one for example gives also interesting perspectives on the topic’s complexity:
Gully’s wishlist - see esp. 3.e about dimension tolerances…
On the one hand, I think dimensioning deserves the same attention as localization (language, number formats etc.) or import/export formats – no matter how good a software is intrinsically, communication and exchange aspects can make or break its destiny.
On the other hand: to my knowledge, the only viable CAD tools that solution the kind of problems referenced here are about ten times more expensive than SketchUp Pro.
A more comprehensive support of dimensioning and annotations is not only a challenge in terms of coding, it requires researching across relevant application fields and locale and would inevitably result into a more sophisticated user interface – let’s hope this product positioning dilemma is getting sensibly approached.