Automatically detect and snap close endpoint

Hi there,

I’ve been looking for a solution for some time now and I did not find a suitable solution yet. I may have not look up with the right keywords… so I will try to post it now and hopefully not bother you with an already solved problem.

I imported the 3d model of a city (.dxf) in sketchUp, then I use CleanUp3 to remove the unused edges and to clean the whole model. This works perfectly fine, all the solids and the entire geometry is correct. My problem is that there is still some very thin space between some of the buildings (less than 25 cm, see picture). Over a small area, I could manually checked and correct this by snapping the endpoints of the disjointed buildings. However, I can not do this for the entire city. Thus, I was wondering if there was a tool detecting endpoints in a close range and snapping them automatically.

Thank you in advance for your help.