motion animation

Hi,
I posted this in the motion area.. but i figured I should post this question here as well..

I have been making some knot tutorials (how to make various knots) using motion.
To make it short, basically I trace a knot with the pen tool, then set write on to animate.
I then use reverse stacking and mattes so the knots are correct where the rope needs to go over or under.

The look is less than desired because i can not create a good looking rope in the paint brush, but thats secondary.. the main question I have is this...
I want to be able to "tighten" the knot after making all its loops.
I tried selecting and moving points, but it takes forever and isn't really looking good.

Is there some behavior that I could use for this?
Maybe select various areas of the rope drawn, and then be able to move it so it looks like it is tightening with respect to the rest of the drawing?

thanks
Kurt

For more realism you might try shooting a video of the knot and rope being tied for a reference. Import reference video to motion 5.
Place your brush layer above your video so you can keyframe trace and color each frame.