I think what you need is [URL="http://www.stclairsoft.com/DefaultFolderX/index.html"]Default Folder[/URL] I have been using it since the days of OS 9, and find it completely invaluable. Its the first thing I install on any new mac I get.

Spotlight is kind of useless as it defaults to a text search of the contents of a file which does not make much sense for a CAD file, other problem is that you have to know the name of the file you are looking for.

Instead try creating a Saved Search that looks only for the file type that you need. Add a date range if you want like last 24 hours and add it to your side bar in the Finder. I am still using CU, so my 24 hour CU saved search looks like this.