Double-Breasted Coat

A double-breasted coat closes with two columns of buttons and a wide overlap.

Views: Front and back, drawn together
Named layers: Sleeve L, Sleeve R, Inside, Body, Front Closure, Collar and Buttons
Anchors: 212 on the front, only where a line turns
File: Editable vector in Adobe Illustrator

How to draw a double-breasted coat flat in Illustrator

Open Flat Library in Adobe Illustrator and go to Outerwear.
Choose Double-Breasted Coat from the pictures. It is drawn on the template, front and back.
Pull the blue points to change its length, width, neck and sleeve. The front and back redraw together, and the figure stops you going too tight.
Insert it into your document as clean, named layers, and keep working by hand.