1,000 floors!?! Wow. Sounds like you’re running out of memory. You’ll probably need to break it off into smaller chunks. 200 at a time, maybe less. Use a GetItemAtIndex with a range for your index (0…199 will give you the first 200, for example). Then close the definition to clear it from Dynamo’s memory and rerun with 200…399 (or whatever) until you’re done. You can probably set this up with DynamoAutomation (a Package) as well to do it in batches.