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.

(Click to embiggen)

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.