Roof by Face - Can't make Roof.

[ctc]

I've created a mass element using the blend tool where both the base and the top shapes are ellipses of different sizes.

When I use the "Roof by Face" tool, select the sloped face of the mass element, and click "Create Roof", revit returns the Error - cannot be ignored "Can't make Roof." My only option is to cancel.

What is interesting is that before I cancel the error window, Revit properly displays the roof that I want to create in an orange color.

[sbrown]

We wrestled with an elliptical roof too and revit just can't make it. I guess the shape is too complex. We ended up using rhino and bringing that form in as a structural family(in-place)