How do I delete a system family viewport in Revit?

To delete a system family viewport type in Revit, you'll need to use the Purge Unused command.

Here's how:

1. Manage Tab: Navigate to the "Manage" tab on the Revit ribbon.
2. Purge Unused: Click on the "Purge Unused" tool located within the "Settings" panel.
3. Check None: In the Purge Unused dialog box, click "Check None" to deselect all items. This ensures you only purge what you intend.
4. Select Viewports: Scroll through the list and expand "Other Styles". Check the box next to "Viewport".
5. OK: Click "OK" to proceed with the purge. Revit will delete any viewport types that are not currently in use in your project.

Important Considerations:

• System Families vs. Loadable Families: Viewports are system families, meaning they're built into Revit's core. You can't directly delete the family itself. You can only delete types within the family that are unused.
• Unused Types: The "Purge Unused" command only removes viewport types that are not currently assigned to any viewports on any sheets in your project. If a viewport on a sheet is using a specific viewport type, that type will not be deleted.
• Impact: Deleting a viewport type through purging will remove it from your project template, potentially affecting future projects if it was a standard type.

If you need to modify a system family viewport type (rather than deleting it entirely), you will need to select a viewport instance on a sheet and then select "Edit Type". From here you can modify parameters, create duplicate types, etc. Deleting a viewport is accomplished by deleting the viewport instance on the sheet.