comping crystals hand

The starting element I needed to created was to erase crystals hand and replace it with the back ground image. Not too tricky as it was shot on a tripod all it meant was too mask the hand and drop in a still from the sequence where nothing was in the way. Then just a case of key framing some color correction onto the background plate when the light changed.

The first initial problem I faced when adding the matched hand to crystals real hand was the joining section from her wrist to the animated hand. Having just the hand would mean that when it dropped it would leave an area of the wrist that wasn't modeled and would be too tricky to paint in the back of her sleeve. Therefore I decided to match a stump base acting as her wrist.

 I then had to rotoscope the area that needed to be underneath the sleeve and thus invisible to the camera. This just involved keyframing the mask frame by frame until a seamless mask had been achieved. I feathered the mask slightly just to make the join a little smoother.







The second stage of the stump was to add some shadows where the sleeve ended and the stump started. This could have been done in 3dsmax by modeling the geometry of the sleeve but I decided it would be easier to just mask in after effects. I duplicated the diffuse channel model and tinted it to all back. The using the mask made for the sleeve I feathered the edges to give a slight gradient on the shadows, duplicated the mask and changed the mode to subtract to give the look of some contact shadows to the stump.

The next part was to add the hand itself. I added the passes into the comp (diffuse, shadow, specular and reflection), changed the modes to : add for the specular, soft light for the shadows, screen for the reflection and left the diffuse as normal. I matched the color of the diffuse using curves and de saturated it slightly as it looked more correct to the original plate. I also boosted the levels of the specular and added a glow effect aswell just to give a little more dull shine to the model.

 












I added a grain match to the final renders also to match further the quality of the video. I had also intended to add motion blur on to the model however after an extensive 39 hour render time for a previous test scene when compositing it didn't look right. The reason for this was that i shot the footage with a pretty high shutter speed around 2500. This pretty much reduced and motion blur to zero especially things not moving particularly fast. The motion blur did enhance the animation but looked out of place in the composit. when I lowered the blur amount to a correct level for the footage the blur amount was so low it wasn't really noticable however it still kept the render time ridiculously high. so the decision to abort motion blur was made.

 












The final element in the compositing I made was a slight glow around the edges of the alpha to look as though the light from behind was engulfing the foreground image. I autotraced the alpha channel of the model which gives a rough mask for the duration of the shot then added it to an adjustment layer above all the other layers and feathered and altered the glow radius until it gave the correct look.