[James Retling]

Found this on another creative cow answer.

Click the layer you want to be the first layer, shift click the layer you want to be the last layer, then cut (ctrl/cmd+x) and paste (ctrl/cmd+v). Voila!

[James Retling]

In After Effects (I’m using CC version), in the comp timeline, select the layer you want to cast shadows. In this case, the layer with ProAnimator. Click the triangle to the left of the layer name to show the Scale, etc and you’ll see The Material Options

Click the triangle next to “Material Options” to open it’s properties. Change “Cast Shadows” to on.

But this is not the end of it! If there are layers “below” this layer (higher numerical value under the # column) that do NOT have the cast shadows or receive shadows set properly, then this will negate the cast shadows option I mentioned earlier.