Hi @SaraJL,
We received the project from tech support and unfortunately the scene which you got back is all we where able to recover.
Apparently, there is a limitation of the amount of data that can be downloaded, however - there is no error message or alert that will pop up to tell you the limitation. If you are downloading data for a very rural region, or a small area (maybe only a few blocks), it's probably fine. But for urban regions it will most likely cause the project to crash.
There is no hard limit in what CityEngine can handle. It is depending on the hardware it is running on and also on complexity of the imported data: Some regions are mapped very detailed in OSM with lots of nodes and many information stored in attributes, meaning that the same extend can work perfectly fine in one region but will lead to problems in another. Additionally the dynamic shapes generated from streets/blocks need resources, there it can help to not create these shapes on import (uncheck Create Street/Intersection Shapes from Graph and Create Block/Lot Shapes from Graph in the Import OSM dialog). For context, there was a similar issue discusses here a while ago: Large scale import from "get map data" in that case CityEngine did run out of memory on import while creating the street network.
In your case the import and creation of the street network did work but then later when the user did save the scene it somehow got corrupted. This is obviously bad and we would like to prevent this in the future.
So far I was not able to reproduce the issue and therefore we don't know exactly how and why it happened. For further investigation it would be really helpful if you still have log entries from the scene got saved.
This would be very helpful. Sorry again we where not able to recover more.
Best,
Jonas