It was a strange decision of Google to strip off the option: http://sketchup.google.com/support/bin/answer.py?hl=en&answer=161784, but anyway there are some ways to deal with it:
- It seems Google feels that they have done something bad and to sweeten the pill a little bit they are offering optional temporary plug-ins: one for Windows and another for Mac... But it can not last forever and with the next version most likely the option will be gone completely.
- One of possibilities is to keep an old working Sketchup version around. It can be kept on a hardware computer or on a virtual one. The former costs more as Hardware + MS license, but it should be fine if there is one extra Windows box around , the latter - is just for MS license (I don't know the deal with Mac). It's a pity there is no Sketchup for Linux, so the only option is to run it under Linux with WINE - some people say that it works.
- Use another program to import DWG and DFX and then convert it into SketchUp file. I know one such program - Alibre. Alibre is a true dimension/parameter driven 3D mechanical development tool (SketchUp as we know is not) and there is a free Xpress version offered. The free version has some limitations as 5 unique parts in assembly, for example, but it still enough for a small project. I actually prefer to use Alibre for part and assembly development and then if needed I export design to SketchUp format. For the exporting there is a plug-in for Alibre called Alibre3DPublisherForGoogleSketchUp.exe. The bad news is that Alibre stopped providing the plug-in for download from its site officially and seems they do not want to support this option in the future, but it is still available from Alibre FTP libraries: http://www.alibre.com/alibrelibraries/ftp/addons/Alibre3DPublisherForGoogleSketchUp.exe; the good one is that the plug-in is still working fine with the new 12.0 version of Alibre.