The Making Of Project Dragon - Episode 10

Its Alive...Its ALIVE!


Today you get to hear about the joy of bringing a dragon to life. As you read earlier, I had planned to add Maya muscle to the dragon rig. However, due to time constraints and technical issues, I decided to drop this feature from the production.

One of the features of the dragon is that it uses a cloth simulation to drive the animation of the skin membranes in the wings. To accomplish this means that a few processes had to be followed in setting up the dragon. First the model of the dragon was broken up to separate the individual wing membranes from the main model of the dragon. This was so the cloth could be applied to just the membranes and not the whole dragon.

This also gave a dragon model which could be animated without the membranes. Once the animation was complete, the membranes then had to be attached to the main model again using dynamic constraints and the cloth properties modified so it acted like stretchy skin and not like hanging cloth.

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As this model had been broken apart and stuck back together, it would no longer function with displacement maps as one single mesh, so a duplicate of the original mesh was brought into the scene, and a wrap modifier was added, which makes the seamless mesh of the duplicate skin follow the cut up mesh of the input skin.

The result is a single model with elastic wing membranes driven by a cloth simulation.

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The Making Of Project Dragon - Episode 9

The Grass Is Always Greener


One major issue that wasn't noted until after the shoot, is that in my shot the dragon is revealed as I come over a grassy hill to see it sitting on its nest. I hadn't considered it at the time, but this would be a relatively large issue during post production. In order for the dragon to appear from behind the hill, I would have to create a layer of the hill in front of the dragon...including all the grass on the hill.
The best solution to this would have been to have shot with a blue screen behind the hill so I could key out the foreground layer. As I hadn't done this and re-shooting wasn't an option, I had to explore other avenues.

The most obvious solution would be to rotoscope out the foreground hill and grass. However, this is a very tedious and time consuming job, and with a 1300 frame shot, would have taken far too long.

The solution I came up with was to recreate the foreground hill as a C.G. model and add some virtual grass to the top. The model of the hill would work perfectly with the match move to mask the dragon and nest as I come over the hill, and the virtual grass would help to break up the harsh C.G. edge of the hill.

The first method I explored to produce C.G. grass was to use Maya fur. This quickly produced a good initial result, though I had some issues as time went on.

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Above is the hill with hair based grass and some stand in geometry in the background. While this result is not bad, I was having difficulty colour matching with the grass in the plate, and controlling the shape of the grass was also somewhat cumbersome.

I therefore decided to use Paint effects. This generates procedural geometry and has a preset for grass. I was able to use this and tweak the settings until I had the desired result. This method uses standard polygons and shading methods within Maya, so it was much easier to match the grass in the background plate.

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Though this early test obviously has some issues, I was very happy with the result. I could produce more natural looking grass with far greater control.

The Making Of Project Dragon - Episode 8

Get Set...


It was decided that some set augmentation was going to be required for this shot. There were no rock formations large enough for a dragon, and it was decided it would be best to simply add a C.G. rock nest. This was a relatively simple modelling job. Basic geometry was created in Maya, then transferred to ZBrush for a high detail sculpt and texturing. The textures were created from reference images taken on the day of the shoot.
The models were than transferred back to Maya with textures and normal maps. The normal maps enable models to appear to have high levels of detail, without having a large effect on render times.

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Above you can see a test render of the nest with some dragon eggs. You can see I added a black colour around the eggs where the dragon breath has left some carbon deposits with its fire breath.

The standing stones around the main body of the nest are there to mask out the top of the hump that the nest in the background plate. This reduces the need for additional set replacement or compositing at later stages.

The Making Of Project Dragon - Episode 7

Just A Little Background


Now this project is planned to be C.G. elements composited onto live action plates. This means that we need to have background plates that we can use during production.

For this project, the background plates were shot on Marsten Moor, a location selected for is distinct visual look. However, the landscape of the location is mostly hilly grassland, largely lacking in distinct features. This could have posed a problem with match moving; the process where the virtual C.G. camera has its movements matched to the practical camera used on set.

This problem had been foreseen, however. To remedy the problem, a series of tracking plates were created. These are white wooden boards with distinct black markers which were placed around the scene. This added a great deal in information for the match move, and helped eliminate any issues that might have occurred.

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With these tracking markers, the background plates could now be tracked with relative ease, but the addition of them to the shot has created a different problem; the markers are now in the shot and don't look very good.

The solution, therefore, is to digitally remove them. This wasn't as easy as it is for some shots, as the camera has a lot of movement in, but I did now have a solid match move of the scene. With this data, I was able to bring a 3D camera and tracking data into after effects. This allowed me to create 3D clones of the shot which could be masked and placed over the markers in the background plate, thus removing the markers.

With this done, the background plate is now ready for production.

The Making Of Project Dragon - Episode 6

Using A Little Muscle

Today I want to show you something that I hadn't planned to add into the project originally, but as I am ahead of schedule, I decided that it was worth the extra effort. What I am doing as adding a muscle system to help rig and animate the dragon.
As you can see in the video below, I have slightly developed the bones I showed in an earlier blog, and have attatched a set of muscles to them. The add a surface for the mesh to slide over, and also add jiggle to specific areas of the model.

Testing of this particular set of muscles shows that I may have gone a bit overboard with the level of detail on the muscles. While they are anatomically realistic, the information doesn't transfer onto the model as there are not enough vertices to take the data. This, paired with the amount of time it takes to set up each muscle with onto the rig and working with the model, means that I will most likely re-rig the muscles, using larger and more simplified muscle groups.

Until later,
Alex

The Making Of Project Dragon - Episode 5

Issues Of Light

One of the key elements that helps blend a CG element into a live action plate is the lighting, and how that lighting interacts with the surface of the model in question. To get an idea of how comlex this can become, take a look at your hand, and see how the light interacts with it. See how there are subtle shadows around creases, tendons and between the fingers. Look at how the light from the computer monitor is reflected off the skin. Think about what would happen if you shine a bright torch against your finger, and how a red glow would shine through.

All these elements need to be replecated in order to produce a realistically lit subject in CG. One solution to these problems is something called image based lighting. Basically, when on location, I took a series of photos of a shiny silver ball from three different angles, then through a series of computer processes, these are unwrapped and stuck together to produce a single image which shows the whole environment.

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(If you look, you can see three images of me taking the photos in the above image.)

Now, this image is then taken into maya and used as an image based light, which is a sphere with this texture on the inside. The image used differs to the above version in that it contains a lot mor information about the brightness in the environment, and it is used to project light of the correct colour and intensity inwards, providing very subtle and realistic lighting. It also gets used to add reflection to the seen, so when used on the dragon, it will reflect the location on the skin and in the eyes.

On the subject of skin, I have kept working on the surface of the skin. I have added an effect called sub-surface scattering, which replecates how light interacts with translucent objects such as skin.

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Now this dragon will probably look quite similar to that in previous posts, with the exception to some changes in the shinyness of the skin. The real difference can been seen when the model is lit with a strong back light.

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Now you can see the light shining through the thin membrane of the skin, revealing the network of blood vessels within.

This close interaction between the light and the surface is maybe on of the biggest elements that need to be right in order to sell an effect shot like the ones I have planned, so I am hoping that this blends in well when we get further towards our end product.

As a final treat, here is a close up shot of the dragon as it stands at the moment.

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Until next time,

Alex

The Making Of Project Dragon - Episode 4

Bones Of The Beast

Today I will go into the process of adding joints and bones to the dragon model to make it possible to animate at a later date.

The first step is to add joints. These are chains of virtual pivut points that the model translates around. These joints need to be laid out to replecate the anatomy of the model, in this case the dragon.

The image above shows the joint layout in the default pose. In this instance the joints have been coloured, which is a result of the skinning process within Maya. Maya supports two main forms of skinning: smooth skinning and rigid skinning. Rigid skinning means that each individual vertex can only be moved by one bone. It takes little computational power to calculate, and is the technique used for many game engines.

In smooth skinning, each vertex can recieve influence from many bones, resulting in a more natural deformation of the mesh at the cost of a heavier calculation.

The rigging process does not end here, however. I am setting up this character with a system called Maya Muscle. In this system, you create bones that have a physical surface, and then add muscles to these structures. This results in the effect of skin sliding over bones and muscle, and can also add the subtle effect of the mass jiggling when it moves.

Here you can see the rig with most of the bones added in. Some of the more important bones are the shoulder blades, the hips and the ribs, as these can often be seen moving under the skin in real life animals. There doesn't need to be a high level of detail in these bones, as they will never be seen. They merely need to have volume and a suface to drive the skin mesh. The next stage is to add the muscles, and that will be revealed in next weeks post.

Until then,
Alex