A recent model search in 3dwarehouse proved difficult re: 3DXchange as almost all model downloads on the site now are for sketchup 2017/2018. Xchange only supports up to sketchup 2015. Whilst I appreciate that there are still sketchup 2015 models available for download on www, 3dwarehouse is the prime source and linked to 3DXchange as standard. Please consider upgrading support.