Wonderful news, we have our script for the supply mechanic! Unfortunately, we did not have a chance to test this. So we are leaving it up to you! Please subscribe here if you are interested in the army supplies submod. Niklas will be by to answer any details you may have. When all goes well, we will wind up integrating this fully into the main pack.
"When a force sets out on campaign, it will start consuming supplies. Depending on it’s environment and stances supplies may be consumed faster, slower or even gathered. Moving a force around a lot increases it’s supply usage. When the force is defeated supplies are lost, when battles are won, supplies will be gained."
- The current available supplies of an army can be viewed when hovering over the supply icon on the general card in the bottom-left corner.