Rotoscoping Street Dancer from Emma Nicholson on Vimeo.

For this exercise we were being shown how to rotoscope a clip and place it into a chosen scene. And for this I needed a short clip of a moving figure with no overlapping of other people or parts of the foreground etc. Then I had to find a looping point int he movement.

Initially we trimmed down the clip to its looping point which for me was about 1.7 seconds. Then to seam;essay stretch it out to two seconds we performed a Time Stretch which adds duplicate keyframes to extend the clip.

We then created an initial mask using the pen tool of the clearest part of the clip, ideally one where the subjects limbs were extended out clearly. I then step by step adjusted this mask to match each keyframe so the sequence was completely removed from the background. One glitch I occurred was the mask in the gab between the duplicate keyframes was randomly generated by After Effects to move from one keyframe to another, not knowing the keyframes are duplicates.So to fix this I enabled the 'Hold Keyframes' options and the mask kept its form until it was manually changed.

Another issue with After Effects is that the lest keyframe is always blank so before the clip loops it flashes off for one frame before starting again. To fix this I had to perform a Time Remap where I moved the endpoint to the next to last keyframe and trimmed the excess on the end. And now my clip looped seamlessly. I could also extend the two second clip to the whole ten seconds now. For this to work I added a simple Loop Out Duration expression into the expression dialogue box.

My Rotoscope was now ready to be added into the scene, for which I have chosen a London street with a large part of clear road where my character will seemingly be dancing. I gave the background a wiggle effect which I learnt from my last tutorial and this gave the background some life which lifted it off the ground.