wall profile

[lcohen]

are you able to create a wall type that is both curved in plan and arched in elevation?

[dhurtubise]

Yes, you can use a inplace to cut the top to shape an arch

[lcohen]

what kind of family would that be?

[aaronrumple]

He's talking about an In-Place family....
Modeling > Create > Select apropriate category....

However, you should look at the massing tools and creating walls based on a face. This will let you use your already defined wall styles.

[lcohen]

can you please tell me what you mean by creating walls "based on face"?

[ws]

It's using the massing tools.

Have a look at this tutorial:
http://www.revitzone.com/index.php?option=com_content&task=view&id=205&Itemid=33

or the free overview on dgcad.com
http://www.dgcad.com/Revit2008-Massing.asp

It allows you to create walls based on a face of a mass object.