With the cut geometry tool you can pick and choose which geometry gets cut and which does not regardless of when you created the geometry.
Revit cut roof geometry.
When you create.
When you create a void it affects only existing geometry.
It will join in the wrong order and you will need to use the drop down menu next to join to switch the join order.
Load the family into the project and place it.
Select the wall and use the attach top base button to attach it to the underside of only the 5 1 2 roof.
Click modify tab geometry panel cut drop down cut geometry.
To enable this open the revit family with unattached voids and click create tab properties panel family category and parameters.
In this case you can use the cut geometry tool to cause the void to cut solids that are created after the void.
Simply select the cut geometry tool then select the floor element first and then select the family second.
You can use model in place when you want to cut system families like roofs or walls.
Cut geometry with the cut geometry tool you can pick and choose which geometry gets cut and which does not regardless of when you created the geometry.
Select the object to be cut.
Then from the modify tab on your ribbon use the join geometry command and select the 7 1 2 roof and the wall.
Load the family into the project and place it.
Click modify tab geometry panel cut drop down cut geometry.
That s more like it.
Slight inaccuracies in the alignment may result in geometry that is invalid causing the cut command to fail.
Another small scale requirement is that geometry cannot be less than approximately 1 32 0 79 mm.
In the family category and parameters dialog select cut with voids when loaded and click ok.
Open the revit family with unattached voids and click create tab properties panel family category and parameters.