Why is the trail renderer drawing squares?

181683-swordtrail-bug.gif

All I did to create this was go to GameObject > Effects > Trail and add it as a child to the sword. This is what the trail renderer component looks like:

I created this project with the 3D Mobile template, if that helps. What settings or properties do I need to change to get this working?

Turns out it’s working, it’s just huge compared to the models I imported. After playing with the trail renderer properties it looks better.