Wednesday, June 08, 2011

Storm Trooper Animation Reference





This is some animation reference that I shot of some friends from work and myself trying to do the stunt for the storm trooper sequence. I used a rope tied to a back pack to get the force of impact as if he was being shot. First in the leg and then in the shoulder. The run was also chosen for it's dynamic qualities - there is a small hop step that I saw in the reference that breaks up the monotony of a run cycle. I think this fits well when he slows himself down by a slight lean backwards as he comes to a stop.

It took a few attempts to get something dynamic and interesting. We developed it into this sequence 1) running to a stop 2) shot in the leg and start to collapse straight down 3) shot in the shoulder which causes a spin while being thrown backwards.

Doing this was extremely fun, and not only that, the final result is way better than if I hadn't done any reference or planning. I always find it a compliment when someone asks if it's motion capture.

Here are some planning drawings that were extracted from the footage. I then used these drawings to set up my key frames.
I did pose to pose animation from the start up until the second laser blast, after which I did straight forward animation. I found this gave the fall a natural "haphazard" feel to it.




Sunday, June 05, 2011

Storm Trooper


I've been interested in the art of Animation and how it fits into Visual Effects for a very long time now. It probably came about while drawing when growing up. I always had this fascination to create hyper real drawings... surreal even, but have it sit in a believable world.

So, for a couple of years now, I've been trawling through the sea of data finding little gems of information here and there about how the movie industry does it. How did they make that transformer leap across the screen with such believability? I've found that it all comes down to one thing...

Light!

Yep that's it.... Light. “That's it”, you may think. Well there is so much in that one little word. So much scientific information; so many connotations. Understanding how light works in the real world allows an artist to create surreal characters that sit so realistically next to their live action counterparts.

So, to get to the guts of it all, I have found that what the pros use is a Linear Work Flow.
When they say linear they're talking about how light works. In the real world if you were to measure light and plot it on a graph it would be represented in a straight line as seen in the picture below (the middle gray line).


Picture referenced from here.
As you can see the plotted graph (middle gray) is a straight line, hence we get the name Linear.

Unfortunately, viewing things in linear on our monitors and photographs would look very dark. So really clever people came up with a way to bend this curve so we can see our pictures on devices and printed media. This is called a Gamma Correction.

So if I were to shoot a video, with the intention of putting a 3D character in it, I would need to know about all the light in the area at that particular time of day or night. And since my camera will be applying a gamma curve on all my footage I cannot use this lighting information.

So other very clever people came up with a way to capture the light at a particular place and time (probably about the same time you shoot your video) without putting a Gamma Correction on it. This very special data is then used to throw light on to a 3D character to light it in the EXACT same way as when you were shooting a real actor.

Hence the name - Linear Work Flow.

In my previous posts you'll notice a whole bunch of really boring photos of train tracks... oh, and a pretty nice one of the Liverpool cathedral. I was learning how to capture light without that Gamma Correction.

In my spare time (not much of that these days) I've been working on a small project. I wanted test out my knowledge and see if I could create my own movie quality scene. I went to the local underpass and shot some footage and captured the light at that particular time and place. I found a nice looking Storm Trooper model from here. I built a custom rig for it too, but I'll cover that in a different blog.

So I've finally completed the animation. I wanted him to do something interesting that would test my mechanical animation skills. So he's doing a run, half a step/skip, a stop, impact from 2 laser bolts and finally a death roll.

I haven't yet implemented the video footage, so it's just lit with the lighting i captured on the day of the shoot. The reason for this is pretty much lack of planning... you see, I didn't know exactly who was going to be my 3D actor, and I shot it at an angle that was too low. This would cut off the head of the storm trooper.

Along with this I also had to learn tracking. This enables the character to sit realistically in your video footage while the camera is moving. I've been delving into Boujou and PFtrack recently. These are amazing packages.

Without any more delay here is a work in progress of the storm trooper (no backplate, using image based lighting, mental ray, 3ds max).




Some interesting places where I learnt about how to capture light without any nasty curves and how to apply that into your work....

Zap Andersen. One of the many clever people your wrote shaders in mental ray
Mental Ray Tips
Understanding Light for the layman

More Clever people -
HDR Labs
Their book is fantastic but you could probably learn 80% of it if you were to read 100% of the website.

Industrial Light and Magic.... How the did it.
Horizons look at ILM and VFX