There are several threads about this subject and there are several people who insist dimensions in Layout are associative. For the life of me I don't know what they're seeing that I'm not. In my mind Layout is a very useful tool for exporting images of the SketchUp model and, if the model is actually complete and no further revisions are expected (a very rare occurrence in my business), a useful tool to output 2D views with dimensions and annotations. But for a 3D model or a model that will go through numerous revisions, I don't see how Layout's dimensions would be useful.
C