Solution for HOK by David Light, Excitech
Start by modelling your form in Rhino.
Then export your model from Rhino as a SAT file, ideally using the export to AutoCAD SAT format. From the file pulldown menu, select saveas > select ACIS SAT from the “saveas type”. The ACIS export menu will appear > select Autocad from this drop down menu.
In Revit Architecture 2008, create a new massing family from “mass family template”. Go to File > new family.
A dialogue box will appear box, select “metric mass.rft” template. This will then open the family editor. You will then be able to import your export Rhino SAT file into the new mass family. To import a SAT file into the mass family. Go to the File pulldown menu > import/link > CAD formats.
Make sure you select ACIS SAT from the “files of type” pulldown menu and navigate to the location where your Rhino SAT file is saved. Make sure you set the scaling units so that the imported file scale is the same as the Rhino file. Therefore, if the Rhino file was created in metres, make sure the import units are set to metres. Import the SAT file centre to centre. The SAT file will then load into the family. Save the family with a suitable name.
Start a new Revit project. Next load the new mass family you created in the previous steps into your project. To load the family, File pulldown menu > Load from Library > Load family and then navigate to the mass family you previously created. This will then load it into your current project.
Go to the Mass tab on the design bar. Pick Create Mass icon; a dialogue box will open warning you that the mass visibility needs to be turned on, accept this dialogue box. Another dialogue box will appear providing you with the ability to name the mass. Provide a suitable name for the mass. The design bar will now change displaying the massing tool functionality.
The next step is to place the mass family you created into the project. To do this click place mass and select your mass family from the type selector. You may get a situation where you can’t seem to place the mass in your project. It is possible that the “place on face” icon is enabled. Change this to “place on work plane”. You will now be able to create additional floor levels within your project and use the “floor area faces” tool to cut the mass at each floor plate. To do this go to an elevation view, create the desired number of additional levels.
Then select the mass and the “floor area faces” button will appear in the options bar. Click this button and the dialogue box appears which allows you to split the mass at each floor level. Select all the levels you want to place a split at, do this by tick the check box at each level. Next select the OK button and the mass will be split at each floor plate level. Once you have split up your mass element you can now start to use the by face tools within the mass design bar to add additional detail to your form. To start with, use the Floor by Face tool.
Select the Floor by Face tool from the Mass tools. Next, Window around the mass form, so that you have the whole geometric form in the selection window. The options bar will now change to include an additional icon for “create floors”. Make sure you have selected the correct floor style from the type selector. Click the create floors icon and Revit will automatically place floors at each floor level.
See also: http://www.wikihow.com/Create-a-Freeform-Roof-in-Revit