What is it?
Camera mapping is a process where a 2d image (static or animated) is projected on to 3d geometry. A virtual camera then can navigate the resulting 3d space in a way which would not be possible before. Since the image now has depth the camera can move in all 3 dimensions. The effect now is more than a simple zoom and pan we could previously achieve with our 2d elements. Even though a camera map offers a lot of movement it has its limitations. We can’t navigate the picture freely since we don’t have all the necessary information for all the sides of our subject/image. We can reconstruct some of those parts but there comes a point where the animation just needs more image information and detail to work with. As you will see in our example if we have an image of a alley with walls left and right we can’t rotate the camera head on to one of the walls. The texture will start breaking up and the illusion will be lost. We could move the camera in to the alleyway and also up and down but not straight on the wall. As previously stated though those limitations can be pushed quite a lot and you will soon find out that camera mapping is a versatile tool that every designer/modeller should have in his toolbox.
Why should I use it?
The reasons one would use camera mapping vary a lot. One reason would be to add interest to a static image. One early example of this can be seen in the film “The kid stays in the picture” where whole scenes are described through a single photo. In order to keep the attention of the audience the director had to find something that would be more interesting than a simple Ken Burns effect. That was accomplished by distributing the separated elements of the 2d pictures in to a 3d space, creating a sense of depth when the virtual camera was moving in it. Since then, and through the use of 3D instead of 2.5D, the effect has improved greatly with the addition of lighting effects and depth of field. This effect is used constantly in documentaries where footage is non existent and only photographs and sketches are used to move the storytelling forward.
One other good use for a camera map would be its time saving abilities! The modeller doesn’t have to painstakingly model every single thing in the scene. With very basic 3d objects the designer can create realistic scenes in half the time it would take to model and render everything in a physically accurate manner. In the movie Spiderman camera maps were sometimes used to build the interiors of buildings the main hero was passing through. Fish-eye photos of rooms were projected on to simple 3d geometry. Thus more time was spent on building elements that were more valuable to the storytelling. In other times it’s used to create shots that would be impossible to do on location like for example in this video.
Having a crane in this location would be difficult logistic wise and maybe even impossible. Instead, a single camera on a tripod can shoot a timelapse that will later on be used to simulate a crane shot.
David Fincher used this effect extensively on the opening titles of Panic Room.
What the tutorial is about
In our example we will use camera mapping to create a sweeper for a tv show segment about movies. The video is quite easy to follow and most importantly only a few minutes long! Enjoy!