At some point, while developing ODB++ input, I realized that Altium provides zip as a container for the format. I knew it was going to be a problem from the start. I checked with the ODB++ standard—yes, they allow any container, not only tar/tgz but also zip or whatever comes to the developer's head. On the one hand, it is pretty practical as finding a zip-lib is easier than finding one for the Unix's tar and gzip. And using zip-container is a kind of standard - rename Word document docx to zip and look inside!
After a year, I have collected some reports of problems:
- Windows makes the zip container almost transparent, acting as a folder. You may not notice it is "the single file intelligent Gerber-set replacement" and may add something or recompress it, creating a deeper structure. Even worse is to allow the creation of the ODB++ file as an unpacked raw folder for the same reason!
- PCB shops want to see the zip file as a Gerber set. You upload ODB++.zip, and they accept it and then delay it. You need to generate Gerbers and upload it again.
- Windows uses file extensions to help users, e.g., by linking a set of programs to handle the format at hand. My installer destroys the user's computer by taking ownership of the default action for the zip file.
For those reasons, I would opt to assign an extension other than the default extension of the container format to the ODB++, for example, ".odbpp." or "odb." and stay with just one container format. The same is true for ipc2581.xml—I don't want something like Notepad++ to open the board file as XML, but a PCB viewer! Of course, a pro will handle this correctly, but not everybody remembers or knows the details.
Imagine all your Word, Excel, or PowerPoint files have the .zip extension!
