Autodesk Revit Architecture

[#1]

I have to create a decorative Gate for a building,

I tried to use a curtainwall but I can't figure out how to make a round mullion or an angled mullion.

Can anyone help??

The shape is basically a circle with an X thru it inside a square, that repeats several times.

[#2]

Yes, custom shapes for mullions are possible, round, angled,...  You need to define a closed shape that Revit can understand as the sketch for an extrusion using the curtain mullion profile template. Once you open the template, there will be some messages that explain how Revit "cuts" the panel when it intersects the profile.

[#3]

You might also consider using a Railing, and create a custom Baluster Family for the gate.

If the Gate needs to swing like a door, you might also consider using a custom Door Family inside the curtainwall

as you first suggest.

A nice trick is you can highlight the curtain panel using the Tab key, then replace it with either a custom curtain wall door, or-- replace it with a Wall ( Duplicate a wall type and create a new one with a very thin thickness ).

You can then insert a "normal" door into the curtainwall--into the "wall" that is in place of the curtain panel.