what is the best way to build a wall-mounted downspout for a roof drain?

[tiho]

What is a good way to build a metal downspout for a through wall roof drain (canale)? 

[sureshchotrani]

Kindly share the sketch or drawing which explains us better.

[ToanDN]

A line based family or a two level family.

[tiho]

any familes out there that actually make it connectable to plumbing fixtures such as roof drains?