by Sahara » Wed May 08, 2019 11:59 am
I have had the exact same issue running SketchUp 2019 and PlusSpec v19 on macOS 10.14.4, this also happened with SketchUp 2018.
Everything was going well then one day after updating the Layout file model reference some walls disappeared from the Layout viewport.
The only way I could get them back was to copy all items on the Layout page and paste into a new layout file then update reference, the problem would fix itself, I could then copy the model and paste back into the original file until I updated the reference again when the problem would re occur.
The only way I have found to stop this from happening is to keep the page count down on the Layout file, so now I have multiple Layout files for the same drawing set which is annoying.