Follow the steps below to add an archway to your plan:
1. Go to Insert Catalogue Items.
2.Click on the doors selector.
3. In the "Item Name" field, type in "iaw"
4. Set your dimensions such as length, height and height off floor for example.
5. You can now add your arch using the usual methods. Note that if you drag it in, you'll also have a window appear so you can add extra criteria.
The end result should look something like this: