About Editing Floor and Roof Shape

You can use shape editing tools to manipulate the surface of a flat (non-sloped) floor or roof by defining high and low points for drainage.

By specifying the elevation of these points, you split the surface into sub-regions that can slope independently.

Shape edit examples

Use shape editing tools to slope a constant thickness floor or the top surface of a floor with a variable thickness layer, to model the following:

• A constant thickness floor or roof supported by sloped non-planar framing.
• A variable thickness material used to slope the surface of a horizontal plane (for example, tapered insulation).

Note: Floors and roofs that have been shape edited will not report a true thickness. The shape editing tools were designed to allow for moderate slopes and, in such cases, variances in true thickness are trivial. However, more significant slopes will increase this variance. Revit will issue a warning when a slope significantly deviates from the expected thickness.

In order to enable shape editing tools, the following conditions must be met:

• Floors must be flat and on a horizontal plane.
• A roof cannot attach to another roof, and the roof cannot be a curtain roof. If either of these conditions is not met, you cannot use the slab shape edit buttons.
  Note: If these conditions are violated later, by element editing, the slab shape edit will cause an error with a callback, allowing the user to reset the slab shape edit.

You can use the following shape edit tools on the Modify Floors tabShape Editing panel:

• Sub Elements
• Add Point
• Add Split Line
• Pick Supports
• Reset Shape

Note: Editing the shape of a floor or roof with these tools does not affect the shape of its structural analytical model. A single analytical model face, based on the original top face, remains unchanged.

Important Considerations

Automatic Folding Lines. In order to maintain the accuracy of the floor/roof geometry, folding lines are sometimes created automatically. Automatically created folding lines will be deleted when the condition that caused them to be created is no longer valid. For example, when 4 non-planar vertices become planar, or when you manually create a split line. Folding lines are drawn using the interior edges subcategory of the element. You are not able to directly modify an automatic folding line. To edit a folding line you must first convert it to a split line. See Convert Folding Lines to Split Lines.

Warped Floors/Roofs. A surface will warp when bounded by 4 non-planar boundary edges or user-created split lines. To avoid warping, add a split line between opposite vertices.