I think I have identified a possible issue with Layout 2021 and how the Viewports are re-rendered when the Model is Updated.
I have attached a screenshot from a Layout Document which shows the issue on the Viewport. This Viewport should be showing a Sectional View, the Ground Floor Layout.
I had to make a minor change to the Model, which I did, and saved. The Sectional Views have all been created with Skalp, for information.
When I reopened the Layout file, and updated the Reference, the Viewport showing the Ground Floor is ‘damaged’. In the Sketchup Model Tray, (in Layout), if I change the rendering mode for the Viewport to Raster and then back to Hybrid, it seems to fix the problem, but can sometimes reappear when Exporting to PDF.
I have noticed this behavior on another Project and thought it was a one off, at the time.
(On the plus side, using Clipping Mask does not cause Exporting to PDF issues anymore, but maybe with one problem being resolved, another has been added.)
On the Project yesterday, It also caused the problem with Exporting to PDF, and sometimes, even though the screen displayed it correctly, the export displayed the messed up version of the Viewport. Took me about an hour to sort the problem last night. As can be appreciated, it is rather frustrating when something so simple takes too long.
Would be interested to see if anyone else has experienced this problem.
I am using the latest updated version of Sketchup and Layout 2021.