Ghost Ship - Closed Q/A Session –
In mid 2002, I was contacted to help work on the feature film 'Ghost Ship', which was to have an October 25th Halloween release. I was brought in fairly late into the post production schedule, upon recommendations from former coworkers who were currently working at Photon VFX in Queensland at the time. I was initially brought in as a shake compositor, to help alleviate the current work load of about 200 visual effects shots. After my initial week working on shake, the company moved me to their inferno, where I was to complete two of the opening shots in the film. I also completed and/or assisted in the completion of five other shots in shake.
Both of these shots were a combination of a live action helicopter plate, several miniature passes, and various 3D elements. Because of the complexity of the shots, it was logical to divide up the workload between several artists. I was responsible for coordinating what elements would be necessary and to complete the shot, as well as completing any fine tuning once the supervisors took a look at it.
Once the live action helicopter plate was shot, it was tracked in 3D, and the information was output to a motion control rig, which was used to simulate the helicopter move on the miniature Antonia Graza. Since there was 3D tracking data, the 3D artists were able to plot the sea level, and render all the water and water effects. Because the camera move was so dynamic (swinging around from starboard to port over the bow of the ship), it was imperative that all the elements were 'locked down' securely to the live action plate, and vice-versa. Any slight deviation from the plate, and all the elements would float, and nothing would stick together.
Given the task at hand, it would seem relatively straightforward that since all the plates were tracked correctly, they would line up and the shot would be done. Unfortunately in reality, this didn't happen. The live action plate was slightly off of the miniature plate, and the masts of the miniature did not line up with that of the live action. Any shadow or light passes that were shot with the miniature were effectively not used, since they would not match the live action masts. Recreating the masts on the live action plate proved easy enough. Several artists were tasked with created mattes for the live action plate, as well as rigging lines which hold the lanterns.
As you can see from the below picture, the live action deck does not line up, and the masts are cut off, requiring stitching work to extend them.
Several miniature passes were shot, which included great shadow and lighting passes. Unfortunately, the deck of the miniature did not line up with the deck of the live action. The solution for this would be to create standin geometry in Maya which matched the live action deck plate, and creating shadow and lighting passes. The bow of ship was recreated in 3D to match what geometry was there, as was the secondary deck behind the live action masts.
Please take a look at this 16.5sec QT (9.2MB) to see a quick making of the third visual effects shot in the show. It is greatly simplified, some elements are shown as a group to make it easier. The second vfx shot in the show is the wraparound from starboard to port of the ship. The reasoning behind accomplishing these shots in the inferno instead of shake is inferno has intergrated 3D tracking and warping using the extended bicubics, as well as the colour warper and modular keyer. It was necessary to use bicubics to warp the live action plate to match the miniature, and the colour warper and modular keyer to get the appropriate masks and colors for the plates.
Feel free to comment on the procedures here, or question why certain steps were taken.
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