The Shake Comp.

1. File-in all the elements. The go to your global settings and hit the AUTO button next to the time range and also make sure to home in your timeline, using the [House] key.



2. Make sure that all the global settings for this scene are correct:



FYI here is a list of video signals and their resolution and field order.

3. You will notice that the default viewer aspect is set to 1.422 which is the pixel aspect ratio associated with PAL video at this resolution (720x576), and what we will be working with. Shake can perform an aspect ratio correction (unsqueeze) in the view port if you desire. I don�t like working this way, especially if I have a broadcast monitor hooked up. Scroll down in the global settings and decide what you would prefer to set the viewer aspect to. For example :



Now on to the actual compositing.

4. Append an Other=>Deinterlace node to the footage and leave its default settings. This will deinterlace the footage so that we can use Roto Shapes. It gets very difficult trying to Roto interlacing lines!

5. Once this is done load the Deinterlace node into your viewer, go to the last frame of the comp and create a Roto Shape for the area that we wish to subtract; the black area behind the door. Name it subtractBlackBG_RotoShape.



One technique for tackling this shot would be to create an articulated matte of the black region as the door opens. A more efficient way is to make this initial shape and then use some �matte mathematics� to create the animating transition. You can see here, I have used two Roto Shapes in the same node. Also don�t be afraid to add a lot of points here this shape is not going to animate so complexity if fine. The next shape will have much less points and will be much easier to animate.

6. Create another RotoShape node and place its points so it covers the sliding door.



7. Select the SubtractBlack_RotoShape and append a layer=>iSub node to it. Connect the rollerDoor_RotoShape to its background input. This will subtract the area covered by the rollerDoor_RotoShape from the other matte. Now we can rotoscope the rollerDoor_RotoShape so it lines up with the moving door.

8. With the iSub node select create a color=>Fade node and then a layer=>Node. Connect the Deinterlace node to the background input of this node. Set the fade value to .5.



This will allow you to see the matte you have created as a semi-transparent overlay while you are roto�ing.

The door does not open smoothly from one point to another so take a bit of time to make this Roto nice. We will add a blur and dilate/erode node later just to clean things up, but try to make it as good as possible!

9. Delete the fade and over node. Select the background plate and append a Set DOD node to it. Set the dod box just inside the white one I have drawn. This will tell shake to only compute data within the box and disregard all other parts of the plate. This is especially useful on big matte paintings.



10. With the Set DOD still selected create a transform=>Resize node and set its resolution to 720x576. Append a Move2d node to this. Now create a layer=>KeyMix node and connect the foreground plate, Move2d node and iSub node to it.



You will have use the Move2d node to reposition the background till it looks �right�. Stacking transform nodes is good practise as Shake will concatenate the transforms if this flow is not interrupted.

We have our composite basically completed, but it is far from convincing. We can now begin to improve the integration of the different elements to create a better �comp�

11. Create a color=>Expand node and insert it between the Move2d node and the KeyMix node. Create another Expand node and insert it after the Deinterlace node.



These two nodes will be used to grade the background and foreground elements respectively. Unless there is a specific reason to maintain colour consistency on a particular element from shot to shot, I generally recommend grading both elements towards each other rather than applying a severe colour correction to one plate.

Rather than suggesting settings for these Expannd I will let you experiment to find values you like.

In this scene we are inserting a very bright background onto a plate that was shot with a practical light inside the �hangar�, even so the edges of the door and the crates still seem to be quite dark and are a bit of a give away. This is not helped by my slightly dodgy Roto!



To remedy this we will perform a couple of simple edge treatments to help �sell� the shot.

12. Select the rollerDoor_RotoShape and create a filter=>DilateErode, and then create a filter=>Blur. Load the DilateErode parameters, set the xPixels and yPixels amount to -1. This will shrink our shape by 1 pixel. Once this done, set the Blur value to 3 or 4 pixels on both Blur nodes.



The resulting edge is a bit nicer:



The next step will be to create an articulated edge matte that we can use to mix the two plates together and create a mild �edge glow� effect.