Creating Shadow-Catching Objects
The sense of reality is greatly enhanced when inserted objects cast shadows onto surrounding objects. In order to have a correct shadow cast onto a live shot, a piece of proxy geometry is needed that approximates the 3-D scene in the area where the shadow is needed. The original imagery is projected onto it, and shadows cast onto that textured geometry.
SynthEyes 2006 can help you build this shadow-catching geometry, using the positions of the trackers that have been determined. This flash capture animation shows a simple example of this.
Here, the trackers from the flybys.avi shot are combined into a single mesh object, and an aircraft flown overhead to cast a moving shadow on the geometry. Normally you'd do this in your animation package, but we'll do it in SynthEyes for fun. Creating the shadow catcher takes just a few clicks in the beginning, normally you'd then export it immediately.
The airplane is intentionally flown over the flat field and the bumpier houses; this contrast helps sell the illusion, without requiring detailed tracking and modeling of the houses, which is achievable but more time-consuming.
After creating the mesh, it can be selected and exported using the "Mesh as A/W .obj file" exporter, and imported into your animation package.
The example also shows the creation of this preview movie that you can view.
