Soft Body Dynamics in After Effects

I have been playing around with a fantastic free After Effects plugin from Rainbox called DUIK . DUIK combines many amazing animation tools that make working in After Effects simpler, but their jewel in the crown is the suite of Inverse Kinematic tools (hence DUIK). DUIK allows the creation of bones and rigs which when added to layers in a comp allow for IK motion. IK means that say you move a figures body, their hands and feet can remain positioned in space, and when you animate their hands, the elbow and shoulder rotations are calculated automatically. Without IK a simple move of the body to the side and a hand wave could involve painstaking and error-prone keyframing of 16 parameters. With IK this simple scenario could be accomplished in 2 keyframes. So yeah – big deal. Did I mention DUIK is free?

But here I want to mention something I came across as I was playing with the bones objects. DUIK bones can be used to control AE puppet mesh pins. A puppet mesh can be warped and deformed using pins that you create at arbitrary points on the image layer. With pins selected, you click the bones button and there they are, all ready to do stuff with.

Normally these bones are used in IK rigs as described above, but I wanted to experiment with another feature – DUIK spring…

My thought was that using spring on the bones with respect to another animated object might give some nice soft body effects. So here is the result:

Actually, what I got looks more like weird balloons than ears, but I reckon tweaking would have got more ear-like ears in the end… I was only experimenting after all…


Create the head – animate it. Go back to frame 1. Create a shape for one of the ears, place over head, and apply 3 pins with the puppet tool – one at the base, one at the middle and one at the top. Duplicate the ear and, with all its pins selected move it over to the other side of the head.

*Now, with one of the ears selected, again select all 3 pins and click ‘Bones’ in the DUIK interface. 3 bone objects are created in place and parenting with the pins is active. Select the base bone nearest the head and parent them using standard AE linkage. Select the other 2 bones, parent them to the head also and apply DUIK spring effect to them, and play around with the settings till you get the right look. Do the same for the other ear. Hit play. Laugh at the bunny with the funny ears.

*OK – now what really happened: in the video, I used a slightly different technique as it turns out I got a bug when I tried the DUIK spring effect, so what I used in the end was another physics plugin called iExpressions which although not free is a great tool for various simulation jobs in AE. I reckon they’ll sort the bug out in DUIK and you may get a different experience anyway so try that – its free!