Decapitation Tutorial in Adobe After Effects



Step 1: Watch a movie
Check out this grisly, yet cool effect of decapitation

Step 2: The concept
Taking somebody's head off is not something I condone, but using speical effects to make it LOOK like it happens can be lots of fun! Again, I know it may look grisly but it's all fake ;)

The effect is created using TWO takes: one take with the actor standing and pretending that his/her head just came off, and one take where you have just a blank background shot. We also move the head (or the part of the body that is being sliced off) from the actor's body to a point off of the screen to make it look like the body part has been tossed away.
Step 3: what you will need
  • Tripod and camera - remember NOT to move your camera AT ALL in between your two takes or your depcapitation effect will be ruined.
  • One important point: when shooting your takes, it's best to shoot your actor's body at an angle such that the camera is looking UP at the actor's body - we do this so that when the actor's head does come off, we don't see INSIDE the stump on the neck left from where the head used to be (we only see the outline of the stump) - this will simplify your special effects for this particular endeavour.
  • Adobe After Effects (computer program windows or mac)

Step 4: Create the decapitation effect!

Setting up the head mask

  • Once you have your two shots, open After Effects and import the video clips
  • Create a new compostioin: composition -> new composition
  • Place the video clip of your actor standing onto the time line
  • Now place the video clip of the blank background onto the time line ABOVE your actor clip
  • Move the start of the blank background layer to the frame at which you want your actor's head (or body part) to start to come off
  • Make sure the blank background layer is SELECTED
  • Now use your PEN tool (in the tool box) to click and cut out a square somewhere in the middle of your blank background layer - it doesn't matter where right now, just make a square polygon
  • Once you've created your polygon it should show up as yellow around the edges
  • Now you want to move/modify your square such that your square/polygon uses more than just 4 points (because we need more than 4 vertices to create the mask polygon that will cover your actor's head when it comes off)
  • To add more vertices, just click on the PEN tool WITH the "+" sign on it. Click on an edge of your polygon - this will add a new point to the polygon.
  • Keep adding points and dragging your points until your polygon just covers your actor's head
  • If you need to, set the mask layer's feather to about 3 (but you can play around with this value): this will create a softer border around the layer that covers your actor's head to better blend the two layers together. Sometimes we have to use a higher feather value if it turns out the two background images have slightly different brightness or lighting tones, i.e. if you're filming outside and the sun changes the shape of the shadows on the ground or the color tone/shading of a wall you are using as a background prop over the course of the day.
  • Once this is all done, your actor should look like they are standing around without a head!
  • Now you want to COPY the video clip of your actor and PASTE it ABOVE the two layers that are already on your time line.
  • Move the starting point of the new layer to the first frame where your actor's head starts to come off (right were your head mask starts that you just created a few steps back).
  • Now make sure the new layer is SELECTED
  • Use your PEN tool to click and cut around the actor's head on this new layer. You should end up with JUST the head on this layer (although you will still see the actor's body from the layer underneath the current layer).
  • Again, this new cut out of the head will be the layer that gets "tossed" off the actor's body when the slicing happens.
  • In the video shown above, I only have this new head layer showing in the movie for exactly 3 FRAMES - the first frame is where the head is just slightly away from the body, the second frame shows the head clearly away from the body and traveling to the right, the third frame is where the head is almost out of the camera view and by the next frame the head is gone. Again you could make the head come off in many different ways but I'm just showing you how I did it.
  • So to make your head fly off, just set the position key frames of the head layer at the points accross your timeline where you want your head layer to move to. Play aroud with it until you think it looks cool!
  • In my example, I had my actor who was doing the chopping swing his sword very slowly so that the other actor with his back turned (who gets his head chopped off) wouldn't be hurt in real life - I just went back in after I filmed the scene and sped up the film to make it look more authentic.
  • Press the space bar on your keyboard to RAM preview your actor's head coming off!