How Centropolis FX Creates Visual Effects

Example 2

A big part of "The Patriot" is the battle scenes, and it turns out that most of the battle scenes contain computer generated soldiers. A good part of the R&D process for this film involved the creation of the individual soldiers and then groups of soldiers that would look realistic and convincing in the movie.

Creating CG soldiers that look realistic in a theater is not easy because the human eye is extremely sensitive to repetition and duplication. People are also very good at detecting artificial motion, even at a distance.

To create realistic groups of CG soldiers, the team at CFX started with real actors trained to perform in revolutionary war reenactments. These actors were outfitted and then filmed on a motion capture stage. The motion capture data allowed the team to create stick figures acting in a number of realistic ways -- walking, loading guns, falling and so on. For example, this video shows the motion capture data for four soldiers performing different activities.

The team fleshed out these stick figures with 3-D models of soldiers and then created four different variations (for both armies) with different heights and widths:

The different soldier models were then applied to the motion capture data to animate them, and then the soldiers were formed into groups.

Motion capture data, wire frame, solid model and final soldier
Motion capture data, wire frame, solid model and final soldier
Motion capture data, wire frame, solid model and final soldier
Motion capture data, wire frame, solid model and final soldier
A group of soldiers

These two videos show the process:

One big part of the project was "dressing" the soldiers -- a process done by texture-mapping different fabrics and equipment onto the 3-D models. In "The Patriot," CG soldiers are only viewed from a certain distance, so advanced elements like cloth dynamics and facial expressions did not have to be incorporated into the models. If they had, the computational load -- already severe because of the number of soldiers -- would have increased dramatically.

The following shot shows how groups of soldiers get added to a scene. Here is the scene as it was shot:

The original shot

This video shows the shot as filmed.

If you look carefully, you can see a number of bushes in the far field, as well as something as mundane as lawn mower tracks in the grass in the foreground! The visual effects for this scene involved everything from changing the sky to redoing the grass to removing the bushes and then adding in two armies. The following pictures show the process.

Removing the bushes
Redoing the sky
Adding the army on the left

This video shows one group of soldiers being added to the shot.

The final shot with two armies

This video shows the shot as it appears in the movie.

These small MPEG files have no way to show the richness and depth of the final scene as it would appear in a theater, nor do they demonstrate the realism of the two armies. When you see the scene in a theater, it is amazing!

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