I have a 3d d3d11 engine and I'd like to create 2d graphics from it as well.

Here's how I typically create the IDXGIFactory1:

Microsoft::WRL::ComPtr<IDXGIFactory1> m_pFactory;
HRESULT hres = CreateDXGIFactory1( __uuidof( IDXGIFactory1 ), reinterpret_cast<void**>( m_pFactory.GetAddressOf() ) );

Here's how I typically create the ID2D1Factory:

Microsoft::WRL::ComPtr<ID2D1Factory> m_pFactory;
HRESULT hres = D2D1CreateFactory( D2D1_FACTORY_TYPE_SINGLE_THREADED, __uuidof( ID2D1Factory1 ), &d2dOptions, &m_pFactory );

Is there a way to create an ID2D1Factory given an already created IDXGIFactory1?

My intention is to combine the 2d factory functions to draw 2d functions given the 3d engine, so I can use convenient 2d drawing functions like: DrawRectangle, DrawRoundedRectangle, drawEllipse, DrawText etc.

Thanks in advance.

Did you have a read the “Direct2D and Direct3D interoperability overview” article? This should go over the process of using D2D in combination with D3D.

@Juliean Thank you. I'll read it.