I am trying to develop a way to calculate checksums between two
separate CAD files to detect if the user changed a model locally. I
have found many programs and code for calculating CRC 32, MD5, and
SHA-1 hashes and they work really well if I have the files closed.
However if I have a file open in the CAD package the code throws an
exception telling me that another process is using the file.

Am I supposed to be able to generate these hash values with open
files? If so, how would I do this? I can't find anything on the web
concerning this.

Thanks,

Brandon