I am currently facing an issue and wondering if anyone could help / that is possible to do. For certain plans such as RCP or electrical, I use a stacking layer system on layout so I can also manage the viewports better. However, whenever I export that to cad, although on paper space all is ok, on the model spacee layout layers go on separate, one next to each other. So the consultants ask me to pile them together on model space (which it sounds silly but it is what it is).
Anyone that faces this issue and have a better way to deal with? Changing the consultants is not an option, just FYI.
In AutoCAD, there is the command CHSPACE, so in theory you can go into one viewport, run the command to transfer the drawing into paperspace. Change the objects layer if required then pick another viewport to transfer the data back into modelspace.
But to be honest - how difficult would it be for the consultant to just move the various plans on top of each other? You could add a reference point in each view to help lining the plans up in SketchUP/Layout.
If you have access to AutoCad, in your case it might be worth your while to try the “Export for SketchUp” export option. This takes everything that is visible on your LayOut page and exports it to Model space in AutoCad. The problem is that the export is using the page scale so you would have to scale it up in AutoCad to make it usable for your consultants.
I have lobbied for years for the option to have an additional "scale export by…"box so you could get a full scale export.