In OBM version 10.09 or 10.10 when the element class is set to Construction the cross frames do not display.
To resolve the issue follow these steps:
- Open the file where we could not see the cross frame members
- Change the Workflow to Drawing and then right in the blank area as shown below and activate Element Class:

- Click on the drop down and select Primary:

- Save Settings on the file
- Change the Workflow back to OpenBridge Modeler
- Open the Cross Frames library from Utility tab and you should see the members.
- Validate the cross frames again and they should show up.
This issue has already been fixed and in future release one will not have to set the Element Class to Primary.