Smoothing out sketch lines

I have been loving synfig so far, especially because it gives you the ability to create jpg’s and Jpeg for comics. My only problem with it is I haven’t been able to smooth out the lines in my sketches. I have seen it in a tutorial, but i have forgotten and do not remember which video I saw. If someone could help me with this it would be really appreciated.

Have you tried tweaking the spline smoothness in the draw tools Tools Options Panel?