AVE previs ready
Christmas is long gone and I’m back in Middlesbrough after a refreshing break. The first thing I had to focus on when I got back was to create a presentation for Advanced Visual Effects where we were to present a storyboard, previs, schedule and a couple of other things regarding the ICA. As I still didn’t have a previs because of work on my Practical Project, this became my main priority.
This is the first project I’m doing which combines CG and live action, green screen removal and 3D tracking. Because of this, I decided to make life a little more difficult for myself than was strictly required by doing all aspects of the work I’m supposed to do in the final shots right in the previs. I did this in the hope that I would gain experience which might help me when doing the real effects shots later.
Basically, I tracked all five shots in PFTrack, modelled and rendered a fairly simple scene in 3D Studio Max, quickly keyed the footage and composited it together using Nuke. As this is just a previs there is still a ton of errors and problems with almost everything. I have continuity errors, issues of scale, existence of contact lighting and shadows in odd places, lack of contact lighting and shadows in others, horrible keying/roto, no colour and grain consistency between shots and so on and so forth. There are also two different actors as I was shooting on two separate days and didn’t have the same people available.
The process of creating the previs took about three days and in hindsight I’m very glad I did it. As a result I will at least do these things differently when creating the final piece:
- Shooting in 1080p instead of 720p to get a better resolution for keying
- Make very sure all forms of sharpening in the camera are turned off
- Shoot a lens distortion grid for every shot to make sure I can accurately get rid of lens distortion (I actually went back and shot grids for the previs, but as the distortion changed quite dramatically with focus and I only had notes for focal length it didn’t help much)
- Be more relaxed about the subject being partly outside the green screen here and there or a cable/tripod being behind the subject as those things can be easily rotoscoped, but making all the more sure the green screen is evenly lit and that shadows are reduced to a minimum
- Adding less contact lighting on set and more in post as the light I got on set was generally too harsh
- Create and import a simple proxy scene of the CG environment to the matchmoving application to avoid scaling issues
- Make sure of continuity between shots – both in the studio and in the CG environment
- Read up on colour grading
