how to make rigg of 2d Continuous track in after effects (Tank wheels)

[Kevin Camp]

if realism isn’t required, you might be able to pull this off using a shape layer and a dashed stroke (animating the offset of the dashes).

try this:

• using the pend tool, create a simple trapezoidal shape using four points to represent the tank tread.
• twirl down the shape layer’s properties to the ‘contents’, click the ‘add’ menu for contents, add the round corners attribute and set the radius to approximate the roundness of the tank tread.
• if the fill property is on, hide it (click the eyeball)
• if stroke is off, turn it on or add it from the same ‘add’ menu as round corners.
• in the stroke property turn on dashes by clicking the ‘+’ next to dashes, then set the dash size and stroke width as needed. you can also set the line cap as rounded if needed.

if you drag the dash offset, you’ll see that the dashes will move around the tread shape. since you only need to move the tank horizontally, we can link that property to the x position of the layer and it will automatically animate as you animate the tank back and forth.

to do that we’ll use an expression. with the dash offset property selected, choose animation>add expression, then copy/paset this into the expression field: position[0] * 100 / scale[0]

now as you move the layer back and forth, the dashes should animate with it.

if you think that will work for your tank tread, you’ll need to add the rest of the tank elements to the comp and parent them to the tread shape layer, animating that layer’s position to control the whole tank.

Kevin Camp
Art Director
KCPQ, KZJO & KRCW