Masters Project – 5 – Video Geometry, Lighting & Process

The image above was created when I accidentally linked a set of lights to the Anna character model that were intended for the video geometry. To prepare, and then to fit, the video geometry into the 3D scene is a time consuming process which involves a few stages. Firstly the video footage itself has to be prepared which I do in Nuke. Each video sequence must first be rotoscoped out of the footage, and this involves setting many keyframes to follow the outline of the elements I want to take into the 3D scene.

The time taken to do this directly relates to how much motion the element contains. Once this is done I also grade and colour correct the video sequence in a way that will fit where I intend to place it in the scene. This process is different for every sequence. Although I shot all the footage initially with my camera set to a flat colour profile in order to ease its processing, that in itself doesn’t make the processing unavoidable. The lighting within the area of the scene which it is to be placed decides the colour tweaking that is required.

In some cases the footage has needed to have areas masked and its exposure changed as it contained strong shadows which wouldn’t fit within the 3D scene. The scene of us both on the bed with Arianne for example required this procedure, and it also required a light wrap to create a glow on the edge of my jumper, my head and the duvet cover to correspond to the light coming in from the window.

The processed sequence in scene next to the original footage

After the sequence is ready it is placed on a flat plane and transformed into position, and angle, within the scene. Originally I was using a script to work out how the plane should be rotated to face the camera, this was taking parameters I was extracting from a virtual camera in Nuke that I would setup to approximate (and check) the angle that the real camera shot the footage at.  This however was causing more problems than it solved, and in some cases I found that breaking the physical rules created a more pleasing look. So I discarded this in favour of placing, scaling and rotating the video geometry by eye. I break perspective and size rules repeatedly during the film in order to create specific visual relationships between the video geometries and the characters. So I’m taking more of a photo montage like approach of editing the elements within the space, rather than following a limiting physically accurate one. For these reasons, the script to calculate plane rotation became useless.

I also have added lights that are linked to each piece of video geometry, these function mainly as fill lights. Although the scene itself has two large windows there isn’t actually much light getting into the scene as I’m not using a final gathering approach during rendering now as its time overhead is too great. However, as I’m rendering out my frames in a 16 bit colour space I have a lot of latititude to increase the exposure of the image. This overall exposure change however only really benefits the normal geometry, which is why I’ve had to create extra fill lights that are just linked to the video geometry.

3D geometry in place with a fill in light (orange dot in the upper left)

Having a fixed unchanging viewing position, and such a large scene depth, has created a film with a very theatrical look to the viewer. To me this ‘stage set’ look involves the audience very well, so much so that I have kept it a lot sparser than I originally intended to. I also think that overall the film has a more meditative quality than it would have had if it contained, as I originally planned, a camera flythrough. Initially I had planned to have a lot more video geometries in the scene that would change quite rapidly. As the work has progressed though I’ve found that taking a less is more approach serves the film much better, and it carries its expression in a stronger way than it would have done if it were more dense.


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