Zombie Speed Run VFX - After Effects Tutorial

User avatarDecember 20, 2012 by Surfaced Studio

Time Remapping to speed up the Zombie

The next thing I did was time remap the zombie layer inside After Effects. I wanted the zombie to move really twitchy and fast. You can enable time remapping simply by selecting the layer and going to Layer -> Time -> Enable Time Remapping. You can then create and drag around keyframes and compress or expand certain time durations on the clip

I created keyframes around the turning movement of the zombie as well as for the 3 running sections of the shot and compressed the space between them to speed those sections up.

Zombie Hunter VFX Tutorial 04 - Time Remapped

This resulted in the zombie turning around in a flash and racing with super human speed from side to side. At each side I let the speed return back to normal so that the running seems even faster by contrast and it doesn't just look like the entire clip is sped up

Enabling CC Force Motion Blur

Since I want the zombie to appear to have super human speed, I added additional motion blur into the scene by applying the CC Force Motion Blur effect to the layer.

Zombie Hunter VFX Tutorial 05 - CC Force Motion Blur

By setting the Shutter Angle to 300 degrees I increased the motion blur on Celina as she is rushing from side to side.

Zombie Hunter VFX Tutorial 06 - CC Force Motion Blur Effect

Creating Shadow Trails with the Difference Matte Effect

Next, I wanted dark shape shadows to follow Celina as she is racing from side to side to emphasise the speed of the movement and add a ghostly horror effect

For this, I added the clean plate photo into the composition.

Zombie Hunter VFX Tutorial 07 - Clean Plate

Because I only used this layer as input to the Difference Matte effect, we can disable the visibility on it.

Zombie Hunter VFX Tutorial 08 - Shadow Trail Difference Matte

Next, I duplicated the time remapped layer of the zombie run and applied the Difference Matte to it. You can find this effect by searching in the Effects & Presets panel in After Effects.

Next, in the settings for the effect, I selected my clean plate as the 'Difference Layer' and set the View to 'Matte Only'.

The Difference Matte effect will detect differences in pixels between the layer it is applied to and the difference layer provided. So compared to our clean plate, we have the Celina zombie in the shot. With the 'matte only' option selected, we will then get a rugged black and white image of Celina's shape.

I also increased the matching tolerance and matching softness of the Difference Matte effect to 13 and 31% respectively to shoothen out the matte so the shape looks more like a ghostly shadow.

Zombie Hunter VFX Tutorial 09 - Difference Matte Effect

Because I want a dark shadow so I can multiply the layer over my footage, I applied the Invert effect to my zombie layer

Zombie Hunter VFX Tutorial 10 - Invert Difference Matte

This gives me a black shadow where Celina's body is. Note that there are some unclean artefacts in the image that we can remove with masks

Zombie Hunter VFX Tutorial 11 - Difference Matte Inverted

I then set my shadow trail layer to multiply and shifted it by a single frame to the right (= delayed it by one frame). This causes a dark shadow to trail directly behind Celina as she dashes from side to side.

Zombie Hunter VFX Tutorial 12 - Shadow Trail

Repeating this process a few more times and delaying each new shadow trail layer by an additional frame adds a nice smooth, ghostly trail to the zombie

Zombie Hunter VFX Tutorial 13 - Multiple Shadow Trails

Here is the shot with 3 shadow trails on top of the zombie speed run base footage!

Note that the clean plate visibility is turned off because it is only used as input to the Difference Matte effect

Zombie Hunter VFX Tutorial 14 - Multiple Shadow Trails

Since I only want the trail to be visible while the zombie is running, I animated the opacity on all the shadow trail layers to fade in only during the zombie run and fade out when the zombie stopped

Finally, let's add some cool particles to complete our zombie run effect!

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4 Comments

User avatar
hosenmahjob
6 Years Ago
December 21, 2012 @ 13:54 am

nice

User avatar
sana singh
6 Years Ago
December 22, 2012 @ 5:22 pm

Nice................

User avatar
Phyu Phway
6 Years Ago
September 29, 2013 @ 7:56 pm

very good

User avatar
vu manh tru
5 Years Ago
April 13, 2014 @ 13:44 am

thank you .good .......my like

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