I had wanted a tunic in this style but didn't have a pattern so I decided to redraft a pattern that I had. I used McCalls 6571 which is a top pattern as the jumping off place.I determined the length from another tunic and used a shift dress to determine the width. I didn't make a paper pattern i just drew the line for the hem extending to the width I had decided on onto the fabric using a gel pen. Then I used the yardstick and drew a line from the armhole to the hemline.
The fabric is a knit interlock that was in my stash.