Tulip Vault Help

[cslaten78249688]

Hi,
I'm trying to construct a "tulip vault" ceiling. I first tried this as an in place model, but realized that it would probably need to start out as a conceptual mass. I can create the 4 sides of the vault, but connecting the sides to close off the angled portions have proven difficult. Below is an image of the CAD plan and elevation that I am working from as well as an image of the mass as far as could take it. I'll also include the mass file for anyone who wants to take a shot at it.

One of my colleagues suggested creating the N/S/E/W sides by extruding the vault shape and then trimming the corners with voids. Then lofting the resulting sides together to close the shape. It's the closing the shape part that I can't seem to achieve.

Any help would be much appreciated!
Thanks,
Colin

[Dimitri Harvalias]

You should be able to do this as an in place model or a mass family using a sweep.
Use the outer boundary of the vault as your path and sketch the curve of the form as the profile. You can then create a rectangular piece to fill in the hole at the top.