For my film VoidBraid I created several relatively complicated CG segments that involved a lot of hidden compositing work. Take this sequence for example:

The bulk of the work on this shot was done in Fusion, which is a Nuke-like node-based compositor. Take a look at the monster node graph for this shot:

Holy cow right! The reason it's so large is that there is tons of invisible work being done here. For example, the rotation and zoom in once we reach the bed area was added in post, and that presents lots of challenges, for example that a section of the forewall and floor area was missing from the original footage so I had to reconstruct it here by reprojecting it from other takes where we did see those areas.

Another un-obvious problem is that once we enter inside the hypothetical cube that represents the room, we can see outside the bounds of the cube on the left. The solution was to digitally paint in an extra wall - that wall on the left as we push in is faked. The same is true of the ceiling through the entire shot. The islands near the bottom of the node graph handle these fakes:

A perhaps obvious problem was the weight of the rotoscoping task involved. I did most of the rotos in After Effects, with a few notable exceptions such as the window frame, which makes use of my match move data to improve its accuracy beyond my own. I brought in the masks from After Effects as EXRs, and the bulk of the network in the upper left was involved with the complicated foreground/background relations of all the various bits and bobs that phase in.

The match move itself was a rather complicated matter. I did the tracking in Syntheyes, but because of the variety in motion and availability of trackers across the timeline of the shot, I had to split the track into three parts: before the camera dollied, during the camera dolly, and once we near the window. Each section had a different fine-tuning step in order to minimize its tracking error, which was necessary because of subtle shakes in the dolly arm, the abundance of large plain surfaces in frame left, and the lack of significant parallax except for the tenuous slivers of landscape out the window.