Technically, you can integrate any kind of transformation in Alfresco. This includes a transformation of Autocad files to viewable formats (PDF / SWF). I have had a few customers which used such an integration. But all of them were using a reasonably recent / up-to-date version of Alfresco, NOT Alfresco 3.0, which is more than 10 years old at this point.
Typically, such an integration involves configuring a transformer worker which executes a local binary via a child process (e.g. using a command line utility). Alternatively, there are transformation tools that would require you to implement some Java code to call a remote service (simple ReST or legacy SOAP). It all depends on what tool you pick for the actual transformation...
