How to Remove Wires, Markers, and People with Mocha Pro

How to Remove Wires, Markers, and People with Mocha Pro

April 11, 2019
Ben Thompson

With Content-Aware Fill for video being added to After Effects recently, you might decide you need additional control over your scene. Enter Mocha Pro!

A lot of visual effects can be additive, but some of them are actually subtractive. Sometimes what you don't see in a shot is a testament to some impressive VFX magic behind the scenes. It's exciting if you have access to After Effects CC, because you already have access to one of the best tools for subtractive VFX in the industry: Mocha!

We’ve already covered how to use the exciting Content-Aware Fill for video tool that just launched in After Effects’ 2019 spring update, and it can certainly get the job done quickly (and often with astounding results). Although, it’s not perfect. You may find yourself needing additional control over your object removals.
What’s great about having both Content-Aware Fill for video tool and Mocha in After Effects, is that you have more tools at your disposal.

You could start off an object removal with Content-Aware Fill for video, and if it works, great! If you need a little more work on your VFX shot, you can easily switch over to Mocha for an even greater level of control.
Imagineer and Boris FX’s award-winning Mocha offers an unparalleled level of flexibility and power when it comes to intelligent object removals. Rather than spending hours rotoscoping and painting over every frame, Mocha gives you incredible results in a drastically-reduced amount of time.

Whether you’re working with a wire removal for a stuntman (or removing the stuntman altogether), we’re going to cover just a few quick tips for getting the most out of your VFX shot in the least amount of time.

How to Remove Wires, Rigs, and Harnesses

Most wire removals involve stuntmen connected to harnesses and wire rigs, but for practical purposes, the video below does the same thing with a puppet wire.

Mocha Pro: Simplifying Complex Removes from Mocha from Boris FX on Vimeo.

Boris FX’s tutorials are always fantastic because of the amount of valuable information they pack into such short and accessible videos. While there is a lot to learn from the video above, here are a few key takeaways to remember.  

First, tracked layers must be ordered so that objects closest to the camera are on top, while objects furthest from the camera are on the bottom. Even though the video is 2D, thinking in three dimensions is paramount when compiling your tracked layers in Mocha.

Next, tracking layer placement is critical for your defined object to achieve a clean object removal. In the example above, the “wire” layer needed to be buried under the “child holdout” and “hand holdout". This allowed both holdout layers to remain in the shot while still utilizing their tracking data to inform the removal of the wire layer.
Also, pay close attention to the motion blur of the object you’re tracking, being careful to ensure that the tracked shape encapsulates all fringe motion blur that occurs. Otherwise, you’ll end up with remnants of the object’s edges after you process the removal.

Finally, the background shape must be tracked perfectly, and it must also completely cover the shape you drew around the object you’re removing. Since the background is what you’ll be using to mask the object, just think of it as a veil that will eventually be placed above your tracked object removal.

How to Remove Tracking Markers

If you’ve used Mocha in the past, chances are you’ve removed a tracking marker or two.  While there are a couple different ways to accomplish this, the method outlined in the tutorial below does a great job walking through a simple solution to a practical, real-world problem. 
The results of the render are outstanding, and what’s even greater is how quickly and easily Mocha makes it to create visual effects like this.

How to Remove a Person from a Scene

Maybe your object removal is a little more complicated. Perhaps you need to remove crew members, extras, or even the actor who is the focal point of your scene. Rather than face the expensive proposition of re-shoots, you can use Mocha to save your existing scene with a ton of control.

Using the advanced technique outlined below, not only can you accomplish this task, but you can vastly increase the speed and efficiency of your object removal as you remove the person from your shot.
Stunning results achieved in mere minutes! Of course, there are times when re-shoots or more complex roto work is needed to get the effect you’re looking for. This is a method well-worth filing away for future reference.

The next time you start a big rotoscoping job or faced with a potential re-shoot, see if these techniques can save you and your VFX team time, money, and a massive headache!

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