General Overview:
The system works by maintaining an up-to-date DWG/DXF file of named ranges in Excel spreadsheets. These files can then be placed (or better yet, linked) in any DWG compatible software. As any Excel user (with Excel2DWG installed) makes changes to the spreadsheet, the DWG/DXF files are updated on closing the spreadsheet. Therefore, the next time a Revit project is opened (assuming the DWG/DXF was linked) it will automatically update to reflect the changes made to the spreadsheet.
On the Excel side:
The program resides exclusively inside Excel and all the work is done from that application. Therefore, you need a Excel2DWG license for each Excel seat that will be involved in editing spreadsheets that CAD users need to reference.
On the CAD side:
This program does not connect to CAD in any way. It does not install any files into its folders nor affect it in any way. It simply provides up-to-date DWG/DXF files that CAD can reference.
When DWG/DXF files are created:
The add-in monitors activity inside Excel. When you or create a spreadsheet with appropriately named ranges, a separate DWG/DXF file for each range is created when the spreadsheet is closed. In other words if you open a spreadsheet and close it without saving, nothing happens with our application.
To prevent wasted time updating ranges that didn't change, the software monitors changes as they are made and remembers the ranges that need to be updated. We have seen spreadsheets with hundreds of named ranges and it would take a long (unnecessary) time to update all of them.