Shot A11: Backdrop Test

I did a quick and dirty photoshop composite of my existing background with some new images I found online. Later I will project a 2D photograph like this one onto proxy 3D models of the buildings and street so that there is actual perspective shifts when the camera moves.

Here is a render of how the composite looks with the new background:

Shot A11: First VFX Composite Test

Scene 4 takes place in the backstage alley of a 1930's Chicago theatre. An actual backstage alley in the heart of downtown Chicago was secured for filming but the surrounding environment and buildings were clearly too modern for a period film. Additionally, the alley backed opened onto a busy street full of rush-hour traffic. A digital set extension would be needed to create an authentic 1930's feel.

Here is a sample of the raw footage


And here is the result of my work this afternoon.



The moving camera meant that before any other work could be done, I needed to create a 3D matchmove for the scene. The matchmove camera would be used when compositing to accurately place objects in the on-screen environment (such as a new wall texture to cover that pesky circuit box). This was done in Boujou 5 and, thanks to the grid-like brick walls, gave a very stable result.



Next up was to key the greenscreen. As this was only a test composite, I did one pass using Nuke's proprietary Image Based Keyer. The IBK takes a very holistic approach and is excellent at dealing with changing gradients and shadows, plus it has only a few parameters to adjust. When the shot nears a final composite I will layer additional keys on top to preserve hair detail, fill in the actor's core matte, and deal with stray pieces that IBK can't handle.

To begin removing the circuit box, I placed a flat card within the 3D point cloud created by the matchmove camera. This means the card will have the same perspective as the original footage and by aligning the card with the 3D points of the circuit box it will seem to "stick" right against the wall. Then I texture the card with a reference photo of the brick wall and, after some quick color correction, you end up with a nice flat piece of wall. Of course right now the "new" piece of wall stands out pretty badly but with some alpha feathering and more tweaking it can blend right in.




The digital background will eventually be a 1930's Chicago street but for now I placed a reference photo of the actual location. The set extension will use digital photos of other, more period accurate locations around the city projected onto simple scene geometry.

I also took 360 degree HDR lightprobe images of the location to use for image based lighting later in production, when I need to render out CG models to match the footage.

Stills from Location Shoot