Rough cut complete for the AVE ICA

This week I’ve delved further into Vue, figured out how to undistort and redistort my plates properly in NukeX and chosen and cut together the takes I’ll be using for the final scene. The cut can be seen below.

To be able to get a good 3D track and also making the CG environment look correct, it is important to undistort the plate before tracking and redistort the CG plate before compositing. As the camera lens is curved and the image rectangular, all lenses produce distortion where what in reality are straight lines become curved to some degree. The amount of distortion varies with the field of view of the lens and also focus if the lens is breathing while focusing.

To figure out the amount of distortion I shot a lens grid for each and every one of the shots in the scene, making sure the lens properties were exactly the same as when filming the corresponding shot. This way, I was able to use the new LensDistortion node in NukeX to analyse the grid and produce a slightly larger, undistorted image; basically by pulling at the corners. I then plugged the actual plate into the node, undistorting the plate itself.

Now that this is done, I can render the undistorted plate and get a better 3D track in PFTrack. This undistorted plate is also the one I’ll be using as a background image in 3d studio max to match my CG environment to the plate. Then, when the CG is rendered, I’ll use the LensDistortion node in NukeX in reverse to distort the CG render; thus shrinking the CG down to the right size and making it look more believable due to slightly curved lines.

It must be noted that in this case, the distortion is relatively insignificant, meaning I could probably do the shot without bothering about it. However, as the distortion can be a lot worse, I feel it is good to get into the habit of doing the thing properly so I know how to do it in the future.