Chroma Keying / Basic Rotoscoping Test
This was my first effort at green screening the ‘giant hand’. The reason I am green screening it, rather than filming in front of the set, is because I will be mixing it with different stop motions and shadow effects, so this way will involve less rotoscoping later.
The effect I have created is not perfect, but okay for a first effort. The hand has a bit of an outline still, and I haven’t added any shadows, but the colours blend quite well. I also realised that I had shot the footage too close for what I wanted for my final piece, but it is all good practice.
Stop motion Test
My video will feature stop motion so I wanted to do an initial test to see how it looked. I watched some tutorials about the best way to film a stop motion, and this is the initial set up I came up with.
I soon realised that the camera I was using was not of a high enough quality and also had no remote, making stop motion difficult. I decided to use my phone camera instead, and purchased a new tripod and bluetooth remote. Unfortunately the remote did not work with my phone for some unknown reason, so I ended up using an app that allowed me to take photos remotely from the computer. Not the best solution, but all I can do for now.
I wanted to have the Lego figure move this arms up (as the giant hand comes towards him) and then add some leg movement (for when the figure is lifted). For my initial test, I experimented with making a hole in the green screen paper, so the Lego figure could still stand on a Lego board.
I loaded my completed test into After Effects as an image sequence, set to 15 frames per sec (as recommended for stop motion). I was happy with the movement of the short stop motion I created, but when I chroma keyed it, I had a few problems. The shadow on the figure was too strong and the holes I had made to stand the figure on made it too dark around the feet area. I took what I had anyway, and put it in front of a Lego scene to see how it looked. Another problem I discovered, was that using the computer to remotely take images changes the ratio to 4:3, but I should be able to correct that for my final piece. Overall, the result is not too bad, ignoring the shadow that is still visible in places.
Although I am not going to use the stop motion I made, I decided to use it as a practice for rotoscoping. I used a series of masks to crop out the shadows and dark patches still visible from the green screening. I could have continued to work on this, as the final result is still not perfect, but it was taking a very long time and this was just a practice run, not the final piece, so I left it here. It was valuable practice though, and I feel a lot more confident with rotoscoping now.
A lesson I have learnt here is to get the original filming to the best possible quality, as this will save a lot of time later, trying to correct small errors in the video. I have also discovered that After Effects runs very slowly on my computer, so the less correcting I have to do, the better. Interestingly, now I have rotoscoped the Lego character better, it looks less realistic on the Lego board than before. I think if I add a shadow to the character it will blend better, so I will have to find some tutorials to help me out here. I think the edges are too sharp now also, so I will correct that next time.
After the issues I had with my green screening, I found this useful (and entertaining) video about how to avoid common green screen problems. I will try to follow this advice next time!
I want to use tracking in my final visual test, so after watching the tracking lecture and the Lynda lecture, ‘Creating a single point track’ (http://www.lynda.com/After-Effects-tutorials/Creating-single-point-track/371399/417550-4.html) I used my previous tests to give it a practice go.
I took the giant hand test and added tracking to a pattern on the Lego figures chest. I then linked the result to my previous stop motion test and rotoscoped out the original figure, so the stop motion figure is lifted by the hand instead. The result is far from perfect, as the stop motion was not timed the same as the hand video, but I mainly wanted to test the tracking, so it was useful practice. Again, the rotoscoping I did was very basic, but I did not want to spend too much time perfecting this as it is just practice, not the final piece.