Let´s talk about stereo-conversion

One and a half years ago I finished my studies of audio and video engineering with a thesis
about stereoscopic matchmoving and stereoscopic postproduction techniques. While my thesis was basically just about the technical aspects and challenges of building a robust stereo pipeline between matchmoving, compositing and 3D it took me almost another year to finish the VFX shots for the movie. Now that I am about to release the darn thing I took some time to evaluate this one little shot that I always took for granted… but… after a few month of not working on it I started to hate the little rascal. While the movie was shot on a Panasonic AG 3DA1 it was actually not possible to change the interocular distance. So I decided to avoid extremely wide or close shots. But in one shot at the end of the movie the camera had to approach the main hero to a very close distance so my two views ended up with a massive parallax shift. I sort of tried to get them together as close as possible. And.. on a small monitor it somehow works. But lets be honest… That wasn´t a proper solution. So I eventually decided to pull a conversion. Actually conversions are a very tedious progress. You have to roto as hell to get a desirable amount of control over your scene.

But… with this scene I was really lucky to get the work done in only a couple of hours. Lucky, because I had a stereocam. Even though I wasn´t able to use my second view I could still use it as a wittness camera for the matchmoving process to get a more accurate result due to the second cameraposition and the thus resulting parallax to start from there on.

Another decision that saved me a couple of hours was to not roto the whole shot but only one frame and project it onto static geometry. even though there was some subtle motion I decided to go the easy way at first and check out whether I could get away with that approach. The geometry was done in Maya and is really simple with some overlapping faces to avoid wholes during the camera movement. And boy.. Am I looking forward to working with Nuke7 and its new modeling tools. Honestly.. working with a fixed camera in Maya is hell because you are unable to Zoom into the viewport to make proper adjustments which would again save so much time if you can shift one or two vertices from the nuke viewport.

So .. just some little tweaks and some paint fixes and its done.  Voilá: nice stereo!

Fell free to compare for yourself !

The finished shot will be released during the next couple of weeks being part of the
stereoscopic short movie “Industrie Dschungel”.

Cheers, Stefan

Native S3D footage:

Converted Scene:

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