By Dennis Collin
For some time, Revit has had several methods of creating sloping slabs. Two of which are with sketching the slab outline and then specifying an edge with an angle of slope. The second is
via the definition of a slope arrow, which specifies height offsets at its head and tail to define the angle of the slope. These two methods are mutually exclusive, as soon as one is defined the other command is disabled on the ribbon.
The third method can be achieved after the floor slab sketch has been completed and we can pick supporting structural beams to define the floors shape. If these selection options are not apparent, check the slab object and see if either of the two previous methods to slope slabs have been applied. If so they will need to be removed before the sub elements method becomes available.
Instead of selecting structural framing, split lines or points can be added manually, usually set out with grid lines or reference planes.
This sort of modelling can be used to create all kinds of building and site features, including simple footpaths, drainage channels and ramps etc. Once points or edges are added, they can be selected with a relative offset to create such features as level spot heights on surfaces, or representative drainage channels.