Yes, there is; you can attach files to your posts. There limits on the file sizes though, and I don't know if you can upload any kind of file (eg, .dwg,. dxf, etc).
Go to the "Quick reply" window below and click on "go advanced", then select the paperclip icon. That brings up the upload dialog box and shows you the size limits of the various file types.
It might be easier to just use Google drive or similar to share a file, especially if you are talking about a file size of 200k or larger..
