Group Editing and Ceiling Hosted Elements

Aaron Maller let me know about an unpleasant bug he's encountered in both Revit 2015 and 2016. If you're thinking, "Boy I'm glad I didn't listen to Steve's rant yesterday." Point taken... It's the exception though, not the rule.

Simple steps to reproduce the issue:

• Create a new project
• Create a ceiling
• Place at least two light fixtures (faced based or ceiling based)
• Create a Group (of the ceiling and both fixtures)
• Copy the Group to create several instances
• Edit the Group
• Swap or move one fixture
• Finish the Group

Where did the other fixture go? It (they) is (are) Excluded. If you select the Group you'll see Restore All Excluded appear on the ribbon. If you use that tool you'll find the fixture is no longer hosted by the ceiling though. It will report in it Host parameter.

If you'd like to avoid this issue then:

• Edit the Group
• Make the changes you need
• Select all the fixtures
• Nudge Up and Nudge Down to put them back in the same spot
• Finish the Group

The copies should be intact, no excluded elements.

I've also found that I can use Save Group, edit the Group in its own file and then use Reload to refresh the Group in the project. This doesn't seem to suffer from the same affliction. Take it slow if your project is using a lot of groups with ceilings. The issue doesn't seem to affect elements hosted to walls, not in the testing I've done so far at least.

Here's a video example of what happens and using Nudge to avoid it.