Monday, March 28, 2011

The next step was to make a rough composit of all the shots. This was for a couple of reasons. The first was that it made sure we knew exactly which scenes needed work and the other was so that we could give a copy to our sound technician, Mattheu Baron. For these scenes we didn't worry about blocking out environments and the lighting was very basic. I made a simple ambient light in each scene set to 1.0 intensity to make sure everything was clear, and we didn't render any shadows.

As we were getting all this done I noticed a couple of problems with the rig we were now using (It was downloaded from Creative Crash). One of the feet was twisting in on itself every step. Apparently this is an issue within Maya, so it was easily fixed. All I had to do was download a hot fix from Autodesk and the problem was solved.

We used lower quality render settings on this rough composit, so when everything came out it was a little stretched and looked a little rubbish, but it had everything Mattheu needed and that's what was important.

So now we split the scenes up to work on blocking them out so that shadows would be cast correctly and things that were supposed to be in front of the creature would appear that way. Unfortunately none of us really knew enough about what came next to do them quite right... Some of them took a long time but until we had the animations through we had no way of knowing that things wouldn't work.

Turns out the process is actually quite simple... You only need to model the objects that will affect the subject, and even then you can take a load of shortcuts. Once I had the animations it was easy to see where we'd been going wrong so I started again and blocked out all the scenes that needed it. Unfortunately because Will hadn't been animating to a blockout there were a few scenes where the creature moved in and out of the objects I was creating. I tried to tweak the animations, but I did so very clumsily and it looked a bit rubbish. When it came to actually compositing we used Will's animation and he masked the objects in AfterEffects. I'll talk more about that later.

I was also lighting all the scenes except for the full modelled ones that Nat was taking care of. For most of the shots I was using a combination of an ambient light and a point light, with varying balancing of intensity. Depth map shadows with a high filter size (usually 5) but low resolution (usually 512) gives a very soft shadow and saves a lot on render time. The shadows themselves were usually very light, sometimes close to white in colour. With the blockouts in place scenes look a little like this:

The next step is to asign a background material to everything you don't want rendered, so in this case the fencing and the ground planes are all background material. When this renders out all the shadows that they create and are cast on them are rendered, and if the creature passes in front of them you can't see that part of him, but the objects themselves are invisible. It's simple but does the job.

There was one shot that was slightly more complicated. Shot 19 has the creature running into the distance, but he passes under a large building which casts a shadow on him.

What I did here, to make sure the shadows fell in the right way, was made two point lights in the shot. One for the creature and one for the building. I then linked them together and it worked out quite nicely. I realize I made out like this was quite complicated. I suppose it wasn't. It took me a while to tweak it right though...

After all the lighting was done we split up the shots, two each approximately. We then proceeded to render (importantly we removed the image plane which we didn't for the rough composit, this is why we had issues with the alpha layer). We did two renders for each shot. The first was a render using maya software so we could get the shadows just right, and the second was using Mental Ray which was to get the best detail on the creature. Next we put everything in to After Effects. We didn't have the audio to make sure everything matched up at this point unfortunately, but we all did our best. The first layer was the maya software shadow layer, then came the mental ray render. That meant we could control things like the opacity of the shadows without affecting the creature itself, so we softened up the shadows yet further.

There was a few issues with my blockouts. They didn't match up perfectly with the environments in the render. You can't really tell unless you slow things down, but what we should have done, certainly for the shots where there weren't many shadows on the objects in front, was mask them in after effects, which is what Will ended up doing with his show anyway.

Once everything was rendered and ready, and Mattheu had got back to me with the audio (sound effects and music separately so we could control levels etc) we could start the final edit in Final Cut. Nat got everything together initially, but the audio didn't quite fit in some shots because of the changes we'd made since giving the film to Matt. Seeing as Nat had done all the editing up until this point I volunteered to take over for these last tweaks to give her a bit of a rest. I had to lengthen some shots and reduce some others so that things worked in basically the right places. The shots where nothing was happening, you may notice looking at the final film, are sometimes a little bit longer than they need to be... But because of that minor problem, you don't end up with all of the sound out of sync. So an important tradeoff. If I had had the raw audio files for everything I probably would have tweaked that as opposed to the video, but we had to work with what we got.

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