Susan,
That's what I thought you meant and there is no easy way to tilt it up.
If you were able to tilt it up would it give you the shape you need ?
Without being familiar with GDL, it seems to me that you have the
following choices.
Make a new library part by viewing the conoid as you want it to appear
in plan and save the 3D view as a GDL object. In this case the 3D view
should be side view, either at 0° or 180°. Unfortunately this method
does not allow you to edit the parameters of the object so you have
set it up exactly how you want it before making it a new object
Make a curved roof with the roof tool at the pitch angle you want
for your canted wall, using the trim to roof command, use this roof to
first cut the top side of a very thick wall, then use the roof again to cut
the underside of the wall.
This method has the advantage of leaving an editable wall.
I don't suggest using the roof itself as the canted wall
because it is made small individual roofs.
If you think that you really need the conoid object then I will look
at the objects code and see how difficult it would be to tilt it up.
Since you are apparently learning Archicad I would recommend
the two methods outlined above as they would be an education
in the use of the program.
Thank you,
Peter Devlin