How to Create a Freeform Roof in Revit

Using a freeform shape imported from other programs (Rhino in this example), we will generate an intelligent roof in Autodesk Revit.

Steps

1. 

   

   Revit Sample Model - Roofs.rvt
   

   

   DWG plan in Rhino
   Extract Plan – export a 2D DWG floor plan from your Revit model for reference in Rhino. You can export a 3D DWG, but be careful when importing 3D DWG data into Rhino without using the bonus tools. Check the units in Rhino under Tools-Options then either Import or Insert the DWG plan as a reference.
   Tip: You can use Rhino’s dimensioning tools to verify the scale of the DWG insert.
2. 

   

   Define profile curves in Rhino
   

   

   Draped shape in Rhino
   Create Form - we will generate a ‘draped’ form using Rhinoceros. This is done simply by drawing a shape curve and a path curve, then using the Extrude CurveAlong Curve tool to generate a surface between the curves. The surface can then be transforrmed into a solid using the Extrude Surface tool. You can import just the surface into Revit, but the flat surface will be difficult to visualize on-screen.
3. Create Model file – Select the surface or the extrusion, use File-Export Selected Objects and select the SAT file extension.
4. 

   

   SAT Imported into Revit Mass
   Generate Revit Roof – In Revit, create a new mass and import the SAT file from the previous step. You may have to adjust its XYZ location before finishing the mass which can be accomplished in plan or elevation.
5. 

   

   Roof by face
   Once located properly, use the Roof By Face tool to generate a roof using any roof type. Pick the top or bottom face of the mass element.
6. 

   

   Walls attached to new roof
   Finally, select the chain of exterior walls, select Attach and pick the new roof as the target.

Warnings

• Be careful when forming an extreme freeform shape in Rhino. Sometimes forms that curve in on themselves will prevent Revit's Roof by Face tool from creating a roof.