I think so, when I’ve been looking at it that what I concluded.I guess its setting up the model for rendering.
I’ll explain how I currently set my model workflow up as background.
I tend to keep a single master model file that I texture as I go, even though I might be generating NPR renders initially, I still texture hi-res for with my VRay materials as part of my workflow, it saves me a lot of time to texture as I go - it makes my model files large but I have a machine that can handle that.
design model file (rendered through SketchFX)
When the design is 95% finalised, I fork the master model file as a master_RENDER file to which I add all the context vegetation and model detail that is extraneous to the general design model - then the files get very large.
same textures as design model file but some veg added (rendered through Vray)
I has been thinking as part of a future Substance integrated workflow, at this point I would re-organise the model around UV groupings and islands. It doesn’t have to be by actual material but by logical islands i.e. ‘exterior walls’ unwrap and islands, ‘Roof’ unwrap and islands. There are lots of general UV unwrap videos on Youtube to help you get thinking about UV islands. There are a particularly good suite of Videos from Richard Yot, “Strategies for UV mapping organic meshes” (not Sketchup related as its Modo but he is excellent at explaining his methods and why) - you gotta pay for the suite but its only about 29 dollars or so and there is a section on hard surface unwraps.
Ultimately, you have to think about the requirements of the workflow, for (my) architectural stuff, I would say maybe 10-15% (being generous) actually needs to be, or I would want to, texture using Painter, most stuff is flat, new, camera position is far enough away and can be handled using decent sized tileable maps (in the above examples probably 40 percent of the textures were created in Substance Designer and the map outputs created used in Vray materials and applied in SU with standard SU and Vray mapping tools - didn’t need to touch Painter.
Also need to consider implications of changes. If the model is changed, I think you would have to re-unwrap that component go back into Painter, repaint stuff, re-generate the maps etc. So again, depends on the output you want
Also bear in mind, the Painter bit of it, I’ve only theorised, Im hoping to find time over the Holiday period to work on it.
Just as an addendum: The design model file size for the example above is 435Mb. The Render_Master model file is 760Mb. Most of this file size is attributable to the texture maps. Many maps are 2k but there are a lot of 4k Maps in there too, some even larger, particularly where I have large tilleable areas, the paving slabs are are large (pixel size) set of maps as is the brickwork where the pixel size can overcome seeing repeatable patterns within a particular shot.