Make sure you place it within the boundary of the floor element.
How to make a sloped floor.
A slant slope situation might be one where over the course of 15 or 20 horizontal feet the floor slopes down one or two inches.
Use one of the following methods.
You can envisage that this point may represent a drainage point in our floor that we want to slope down to.
If we switch to a 3d view it is far easier to see what is going on.
Mix up some concrete mix in the mixer.
As soon as you place the point revit resolves the new surface by triangulating it.
You can create sloped floors in the building model.
Draw a slope arrow while sketching or editing the floor boundary.
For example a floor that extends 4 feet away from the drain should have 1 inch of overall slope.
Specify a value for the defines slope and slope properties for a single floor sketch line.
Mark this outer height mark along the wall with a pencil.