Open Clip is currently only for Mac, but if it is available for Windows, we could easily support this.
Transferring files with other programs is still pretty easy on Windows, and we have a lot of users that will just WBlock their desired part in AutoCAD, and then import that DWG file into bonzai3d.
Also, in bonzai3d there is an option to Export only the Selected entities, so if you only want to transfer part of a file, just pick that and export using this option...