Hi!
I am currently working on a site model of around 5000ha so it’s pretty huge. To avoid problems while working, I worked in different files. As I’ve completed my work now, I need to merge all files (4 files ranging from 15mb to 49mb). The only way I know how to do is by copying and then using “Paste in Place”.
But it’s extremely slow and ends up crashing most of the time.
Is there any other way to merge all these 4 models in one?
Thank you!
File > Import - SketchUp files
Yes! I tried that too. Didn’t work either. 
Slowness comes also from edge/face merging/intersection. You shouldn’t have edges or faces at the top level. If SketchUp only find groups/components at the top level (which don’t need to be intersected), it should be faster.
If they are geolocated accurately, you can use File → Import and the imports should be positioned correctly, but wrapped in a component. Exploding that component (if you need to) then again takes potentially more time for merging/intersection.
If not already done, have each of the 4 files on it’s own layer and have them hidden while importing the next.
If you have components that are “heavy” and a large number of them, (like say a bunch of screws with fully modeled threads), you could first change all of those to much simpler placeholder component geometry. Then once the model is together update/swap for your desired more complex component.