Sketchup

prerequisites:

units:

Find this dialogue in window > model info

plugins

Install this OBJ exporter plugin. Unfortunately Sketchup’s native exporter is verbose and dramatically increases loading times. We will create our own plugin eventually, but this will suffice for now. Once installed please got to :
 

 
And wait for it to finish exporting. Unfortunately there is no loading bar, so you know its finished once the obj, mtl and assets are generated.
 
 
 

3ds max