Subdivision modelling makes every model big and Sketchup is not really made for big files. But when you know what you’re doing it handles it ok. Making not too much visible while working on certain parts helps to keep the user interface fast.
As opposite to Sketchup V-Ray 3.40.02 doesn’t have any problems with big models. That’s a major difference to the 2.x version which really needed a long time to start rendering. I’m still working on my little concept with a lot of trial and error but getting there bit by bit.
Love the new bump map option ‘Edges’ in V-Ray which allows you to create round corners while rendering instead of modelling them using a plugin like Fredo’s round corners. Works really well to make more realistic renderings of especially small parts which are too little for the round corners plugin/sketchup.