un-merge model from import.

I exported model of streetlight.dae (DAE file) from SketchUp Make 2017 then import asset DAE file of model to Unity 5.6 but they are apart object. Show here:


I tried merge the object in one model in AutoDesk 3ds max then export to FBX but it’s still not merge. I think maybe I should check it again. How you can merge model all in one? I don’t like buy SketchUp Pro $700 dollars but maybe I should?
Heidi.

I found it read from person had same problem too. Too many ID's when importing Sketchup model - Unity Engine - Unity Discussions