The last time I did rotoscoping, the result was very messy and I didn’t feel like I understood the technique, which is why I’m quite pleased that we had another lesson on it! We recapped what it is is and why it is used as well as getting introduced to roto work in After Effects.
What is Rotoscope?
My definition: rotoscoping is a technique used in film when footage is traced, cut out and overlayed onto a different piece of media (usually footage).
Actual definition: Also known as ‘rotoscope’ or ‘roto’, rotoscoping is the process of tracing objects and characters in order to remove or edit them from footage. Usually, chroma-keying is used to do this as it is much faster, however, when it is insufficient or unavailable, roto artists use this technique to manually lift and move pieces of footage onto different backgrounds, videos etc. An eye for detail, patience and good use of the pen tool are all skills required to effectively roto.
– Here is an incredible demo reel that shows the power of rotoscoping –
After Effects: Rotoscope Recap Demo
We opened up the program and listened to the demo before trying it out ourselves. I will be combining everything here though, talking about my process as I followed the instructions. After importing the footage we were going to be using and specifying which section specifically we were focusing on, we were told to select the layer and click on the pen tool. Anything drawn with it is converted into a mask and we were told to start anywhere, drawing only sausages and circles. The problem with this is that as soon as I created a shape, the footage was hidden from me and I could only see inside the mask. To fix this, I duplicated the layer and put it underneath, after which I clicked the little lock icon to make sure I didn’t edit it by accident.
When adding shapes, we were told to overlap them and make them relatively small since this would ensure every part of the person is covered and the edges can be captured more precisely.
Big shapes go in the middle and sausages on the edge for the detail so that more precise control can be reached. We don’t use one shape because rather than moving the points, you can copy and paste/move the smaller parts. One shape is inefficient and hard to work with.
Now, these shapes won’t move unless you tell them to – in other words, the masks need to be animated. This is done really easily by going into ‘mask’ (clicking the layer and ‘M’) and ensuring the stopwatch next to each is turned on at the beginning. This creates keyframes for every single one and any movement afterwards is recorded. Now was the hard part: moving the shapes according to the footage. This takes the longest because precise movement needs to be captured, and the overall shape also changes quite a lot, which means that sometimes, the original masks can’t be used and have to be altered to fit their new space.
I also released that I was struggling to differentiate between Phasma and her background since the colours were quite similar. To make it easier on myself, I added a Curves effect to the layer underneath and darkened it, to make the masked area more visible.
We were given a quick demonstration on animating the masks. I think that this is the part I struggled with last time since I certainly had a hard time this time. Phasma’s armour was relatively smooth and simple, yet her form changed so much in that simple action and I kept having to tighten or enlarge the masks. A useful tip I learned is clicking on the mask path allows you to move the entire mask, and clicking on the video layer allows you to move the individual points of a mask. I swapped between these a lot throughout.
First, I jumped to one second and adjusted all of the masks by moving and changing their size. This took a long time and didn’t leave me with enough to spare for the part afterwards, which is how the precise roto can be achieved. I was meant to go back through the space in that first second and anywhere that the masks slipped out of place or weren’t following the exact edge of Phasma’s shape, I was to fix it. I started to do this and was aiming to have keyframes at least along the half-second, but I didn’t get quite that far.
I found it really frustrating how I needed so many sausages and circles for a more precise outcome, but the overlap of their many lines and colours made it confusing to move them to the place they were supposed to go and it ended up feeling like a mess again, like last time. Looking at the screenshots now though, I think I have improved greatly in how I create the masks needed. I followed the things we were told not to do quite strictly:
- Don’t click a bunch when making a mask. Too many points make it more confusing and increase the render time.
- Don’t click too little either, there need to be enough points for the shape to be round. Avoid anything clunky or straight unless it’s in the middle (but even then it’s best not to).
- Don’t spend time rotoscoping pointlessly. The main goal is to remove the foreground from the background, so why would you outline details that are not along the edge?
These rules made clear sense to me and even if some of them could help speed up the process, I avoided them. I think that I was doing a pretty good job throughout the whole process actually, but the lack of time and experience made it hard to not get stressed and jump ahead. You really need to take your time with this in order to achieve professional results.
I didn’t really finish the main part of the task as I said, but we were shown how to do the next part and I had to move on. Here are the instructions:
- Create a new solid, choose your colour to be mid grey (H:0, S:0, B:50).
- Place this new solid behind the layer that contains your roto and scrub through your footage.
- Look for edge bleeding, mask slippage and any areas not covered but current masks and apply fixes to your roto.
- To apply a checkerboard, select your solid and apply the checkerboard effect (effects > generate > checkerboard). Play around the width scaling to suit.
Here is the final result from following the demo:
As you can see, it’s shaky and unrefined and towards the end, I didn’t manage to create masks for her turning around. However, it’s also a massive step in the right direction! I remember my previous render, with an elderly man walking forwards. I tried to rotoscope his hate but it failed miserably and I was unsatisfied with the lesson outcome. At least I managed to do something that resembles a rotoscope render with this attempt and I’m quite proud of the little that I managed to mask out. It’s only one second and could have done with a lot more work but I am happy to have had the opportunity to practice again and go over the actual technique.