How to Animate a Spider in After Effects - Without Keyframes!
2021.07

Some time ago we celebrated our fifth anniversary with hand-animated GIFs. Each GIF we created was completely unique in style. Some of them were not only an opportunity for us to let off steam, but also a test if and how the animation techniques work and how elaborate they are in the end.

The example we present today is about animating a 2D spider in After Effects and this is what it looked like in the end (and no, we don't hate spiders or insects!). Our office spiders are gently escorted out the window by us, if at all!):

Visit us Weltenwandler on GIPHY

This is how 2D animations are created:

We have summarized the process from the first sketch to the final character animation for you in this small but nice video. A time-lapse that shows the individual steps.

How do you animate spider legs in After Effects?!

The spider legs were not animated with keyframes, but with linked expressions. Each of the (still intact) legs of this pitiful spider consists of four graphics. The anchor points are set in such a way that they would lie exactly on a 'joint', as explained in the following image:

Arrange the graphics correctly!

In AfterEffects the graphic layers are arranged on top of each other in a double sense. First, the anchor points are each above the end points of the previous leg graphic, and the layers in the Layers panel are also on top of each other (At the bottom is the first leg graphic, at the top is the spider leg). The layers were additionally attached to each other (with the Pickwhip tool in the PARENT panel).

But now to the actual animation:

The first leg element has a WIGGLE expression (we will explain all used expressions in detail in a moment). All other graphic layers above it have an expression that references the rotation value of the layer below. In After Effects it looks like this::

In the code (for you to copy) it looks like this:
…

Ebene Bein3-8.ROTATION = [ value + thisComp.layer(index+1).transform.rotation.valueAtTime(time - 0.1 )*3 ]

Ebene Bein3-7.ROTATION = [ value + thisComp.layer(index+1).transform.rotation.valueAtTime(time - 0.1 )*1.5 ]

Ebene Bein3-6.ROTATION = [ value + thisComp.layer(index+1).transform.rotation.valueAtTime(time - 0.1 )*1 ]

Ebene Bein6-1.ROTATION = WIGGLE

…

The expressions explained in detail:

wiggle (4, 12)

This generates a random value. The value B is the repetition per second and the 12 is the strength of the change.

VALUE

This is the original value of the layer, so that you can still set the rotation despite the expression.

hisComp.layer(index+1)

One layer below.

valueAtTime(time - 0.1 )*3

0.1 Seconds later + *3 = the original value multiplied by three

Thanks to the expressions, all the leg limbs move like the first one and amplify the rotational movement. To make it look more organic and natural, a minimal time offset was added. This way you can animate really complex structures, like a whole carriage including driver and luggage (like in THIS example).

Everything all right so far?

If you still have questions about expressions in After Effects or you would like to give us feedback, please feel free to use our contact form. We always have an open ear for project inquiries ;)