Why do my scenes change style when i reopen a file?
Typically it’s because the reference is being updated to match the SketchUp file. What you describe can happen if you modify the scene in LayOut, for example if you change the style in the Styles tab of the SketchUp Model panel in LayOut.
Best workflow is to avoid modifying the scene in LO. If you need to make changes to the style or camera position or other scene specific settings, do that in SketchUp and update the scene. Save the changes and then update the reference in LO.
There should never be any reason you need to have modified scenes in LayOut.
The separation of Sketchup and Layout has benefits but also problems. The most obvious of these is knowing when the Sketchup file on which a Layout drawing is based has been changed. It is also affected by how you open the Sketchup file.
LO is generally set up so as to only update its SU file reference if told to do so. If it recognizes that a SU file has changed since you last opened LO it will offer to update things when you open the related LO file. If you say yes, scenes may change because the originating SU file has changed. Otherwise, it usually requires a more manual approach where you choose to update a window in LO by right clicking and forcing an update.
This process is different if you first open an LO file, right click on a window, and then choose Open with Sketchup. In that case, any changes you make to the SU file will update the LO file on the fly.
Providing you know all this, it works fine. Of course, as @DaveR has pointed out, you should never modify a LO window as that breaks the link with the SU file. This is one of the many things in the Sketchup world that you can do but is recommended that you don’t.
This is a gem of information, thank you simoncbevans
OK then, but if changing styles in Layout is so problematic - why was it ever added ?,
as intuitively that what most users will do…
Frankly,
Model changes should be controlled in the Model [SU] and
Presentation should be controlled in the presentation {LO}
not the spaghetti mess we have at the moment…
Hopefully all will be addressed in 2019 !
[20 minutes later and further testing]
Actually, now I am even more confused ???
I changed the Style in LO.
I got a [modified tag] appear in the the Model Tray
[something we should avoid as the link is now broken]
I then went into my SU model added some objects ,
confirmed the Scene style was unchanged there
Closed my LO file
Reopened my Layout file
the style I selected in LO was still active [not the SU style]
and the objects I edited in SU were updated in LO [as I hoped and would expect]
ie the link was not broken regarding Style changes in LO
Aghhh this is why I find LO so inconsistent!!!