There is one way you can implement your project to achieve this result. Our existing structure is deformed without a false ceiling as follows.
We use the existing structure and the drag & drop function as well as copying the elements while holding down the Ctrl key for quick modeling. It is important to ensure that the existing pinned connections are displayed correctly. In this example, only one workflow is to be displayed so that the connections between columns and slabs are modeled rigidly. The bottom columns are modeled as nodal supports using the Column in Z … function.
The false ceiling should not transfer any loads to the existing continuous columns.
To compare both models, you can evaluate the results using two substructures modeled in a file.