Create you floors in the normal manner first.
Revit how to make floor.
In this video we take a look at how easy it is to create floors for your revit project.
To sketch the profile of the floor click modify create floor boundary tab draw panel and select a sketching tool.
Click modify mass tab model panel mass floors.
In the mass floors dialog select each level that needs a mass floor and click ok.
You can select the mass in any type of project view including floor plan rcp elevation section and 3d views.
You can use shape editing tools to manipulate the surfaces of your floor elements.
Mass floors are based on levels defined in the project.
You can cut openings in the faces of these elements or you can select the entire element to make a vertical cut.
Remove all shape edits to your surfaces by means of the reset shape tool.
Once created select the floor element and then use the shape editing tools accordingly.
The floor boundary must be a closed loop profile.
If it is not active click modify create floor boundary tab draw panel pick walls.
Click by face or vertical.
Structure tab opening panel.
Select walls in the drawing area to use as floor boundaries.
Using the dwg we imported earlier we draw the outlines of our floors.