VFX1 DD1410: Altar Sequence, Blue Screen and Close Up Shots

The altar sequence piece requires rotoing, tracking, transforming and keying. As seen in the previous blog post regarding this piece (see link beneath this paragraph), this blog post is regarding the four blue screen shots involved with this piece.

http://darthspockvfx.blogspot.co.uk/2012/11/vfx1-dd1410-altar-sequence-rotoing.html

Lets take a look at the first blue screen shot, this is Shot Two, the shot consist of one of the female characters looking up at a blue screen (see picture below).

The first step is to create rotos around the girl and the surrounding area, this is to be used with the keylight nodes later.

Now as seen in the picture below, three keylights are brought in, an inner, an outer, and a final one for the character, this has been named Shot Two Keylight.

Lets start with the inner keylight.

This is the inner keylight showed in the alpha channel:

Next, the outer keylight:

Now finally, the Shot Two Keylight (this is the one used to get the most detail on the character to prevent any blue screen spill):

The next step is to read in an image to use as a background, after the image has been read in a reformat node needs to be read in to scale the image to the same size of the footage. Merge the reformat node with the Shot Two Keylight.

View the merge, and the image will now be in the background.

The next three blue screen shots (Shots Four, Six and Eight) are all pretty much the same, it is the group of children standing in front of the dragon statues and altar with a blue screen behind it. The only thing that changes is the positions of the children. Shot Four is going to be used as the example in this blog post (the footage for this shot is below).

Lets start with the inner keylight:

Now the outer keylight:

After this, individual keylights are made for the dragon and altar (with the children in front of it), the boy, the girl who walks in and the crease along the bottom of the blue screen.

The Dragon and altar (the picture shows the keylight with the roto attached to it):

The Boy:

The girl walking in:

And finally the crease:

Merge all of the keylights together:

Just like the last blue screen shot, a background is needed, so the background needs to be read in and reformated.

 Just for a bit of variety, a magenta image has also been used to show that two images that are completely different colours can both work.

There is still a bit of spill coming through, in particular in the left hand bottom corner. So a roto node is brought is, roto'd around the spill, and used as a mask.

Finally, a hold out matte needs to be created around the children.

And that's it, the same thing applies across the next two blue screen shots, they may need a little bit of adjusting slightly and the hold out mattes for the children need to be adjusted for the children's new positions in the shot.

There are three close up shots throughout this sequence, these are shots three, five and seven. Shot five (see reference picture below) doesn't need anything done to it.

Shots Three and Seven both need to be stabilised, this require a tracker node and a transform. Once the shot has been tracked, the transform is used to scale in the shot so that the picture stays in shot now that it has been stabilised (see the example shots below from shot seven).

That's all of the altar sequence shots done, the next step from here will be to make sure that off of the rotos in each shot have a lifetime that applies to the frames in that shot. This can be achieved by selecting the roto, going into its properties, selecting life, and give it a specific frame range (see picture below).