Levels.Selection node dropdown available, but output shows null after re-opening script

I’m new to Dynamo, and not sure if this is a bug or if I’m doing something wrong. Google search on the topic reveals nothing.

If I create a new .dyn and use the Levels.Selection node, all is well, the output shows a Level from the model with it’s name and elevation.

As soon as I save my work and re-open that same .dyn later, the levels are still available to select from in the node dropdown, but their output value shows as null. Changing my level selection and replacing the node make no difference. Only starting another new, blank .dyn file brings back the Levels as anything but null.

Hi @7UXJG welcome them to the community!

Which version Revit?

Thanks! I’m on Revit 2021.1.3.

Did you open in a different file?

I’ve tried it on several Revit models including a blank one with just one level. Same result every time. In fact, it is more than just the levels node. All the nodes go null after I save and re-open. Found some forum posts eventually that indicate that the problem could be with one of the dynamo packages I have installed. Is there any better way to isolate which one, other than deleting them all and re-adding them one at a time until it breaks again?

@7UXJG Check if you have similar problems that’s outlined in this link. Also try to follow the steps mentioned there to see if it clicks for you.

It does not seem to be a similar issue. I can write in the code blocks, just all nodes return null, even the extremely simple inputs like selecting a level from the model. Also Dynamo is not crashing.