Revit Export Setup - Walls

I am trying to create a custom export setup and started with the walls. I noticed that walls are catagorized by the function parameter under construction. This is not working for us because many of the wall types are used for both interior and exterior. I need to create a new parameter that I can add to the walls so that I can assign CAD layers to them by subcatagories that I have created myself. I just need to know how to add an additional parameter to the wall system family. Can anyone help me do this?

Thanks in advance!

I don't think you can. It appears that only the default properties are available. If this weren't a wall and were just a family I would tell you to put it on it's own subcategory which would then be available to you in the CAD export dialog. But then I don't export to CAD much at all so I might be missing something.

What I would recommend is, if you have an interior wall and an exterior wall that are the same wall type (which seems odd but okay), you make them as separate wall types anyway so you can control what layers the exterior and interior wall types are assigned to.

Thanks greg. I don't know if that would work for us because that might be confusing to have so many wall types. The project we are working on is an underground structure with many CIP concrete walls. I tested adding a new subcatagory to walls and it did show up in the CAD export settings, however, it did not show up under the wall properties when I clicked on a wall. I need it to show up under properties so that I can customize it.

Katie
To understand the workflow you are trying to create I have a question for you how and who will be using the Autocad files that you are exporting?