In the prior post in this series, I covered how John and I worked with friends, spouses and significant others to create a Mad Scientist’s Lab in the basement of his house for our short film Blobageddon. With the lab created, we needed to move on to what one does in Mad Scientist’s Lab – blowing up the world. Here at For Zombies, we don’t think small.
We already had the instrument of destruction in the lab. The “Big Red Button” with the ominous label “Start Antimatter Reaction”. We worked our friend Bob into the scene because he has to die in our films, and at least this time we’d let him go out with a bang.
Following is the edited but unaltered sequence
Here’s how it came out following post-processing:
First off, note the use of sound effects. We set everything up with a nice closeup of Bob’s gloved hands pressing the button and added a sound effect from Garage Band of a steel vault door closing. Next we added klaxon sound effects that were also from Garage Band.
However, I know you’re really wondering – “Where the heck did those red lights come from?” and “What’s with that static effect at the end?
The red lights and static effect were both digitally generated by Adobe After Effects.
To get the red lights, we took the base footage and added a Solid Red Layer over the top of it.
It’s all about the layers
Note the Column called “Mode”. It’s set to a value of “Overlay”. This allows us to blend the top layer (red) with the bottom layer (the video we shot), preserving shadows and what not from the bottom layer. Then by playing with the opacity of the Red layer, we can control how much red is actually seen.
Here’s a shot of an unaltered frame:
Ho hum – nothing to see here
And here’s the same frame with a red overlay set at 67% opacity.
Maybe I shouldn’t have done that
In the real video, the red lights flash in and out from 50% to 100% opacity and back down every second. We could have done this by manually animating the opacity over and over again, but that would be a pain in the ass, and tweaking it would suck. Rather, as John and I are both software developers, we leveraged After Effects Expressions and came up with an algorithm to do this for us:
fr = Number(timeToFrames());
n = ( fr % 30);
if ( n > 15 )
n = 30 – ( n – 15 );
n = n + 15;
pct = n/30;
(pct * 100);
What this does is over the course of 30 frames, run the opacity of the red layer from 50% to 100% and back down. The reason we used the number 30 is that the video is running at 30 frames-per-second. Mix that with the klaxons and all of a sudden we have a lab going into “red alert”. Pretty cool huh?
In the next article in this series, I’ll cover how we made the static effect at the end of clip.