Friday, June 11, 2010

Look Development in CG

For this quarter’s new media project I focused on look development and style in 3D graphics. The class gave me an opportunity to explore look development in computer graphics and experiment with processes I don’t usually get to use. The end result of the project was a scene modeled and textured in Maya with one animated shot and two still images. In the first step of the project, I outlined three contrasting styles based on reference images of paintings and renderings created by other artists. Next I set up the constants for the projects. These were the elements of the project that would remain the same between looks. The constants included all of the modeling and camera angles. The constants provided a way to evaluate each image as a set and provided a clear link between the images.

Look 1

The goal of the first look was to base the image on 18th century Dutch landscape paintings like those painted by Rembrandt. The imagery, while not photorealistic, was a stylized version of reality. I used a limited palette and pushed the colors into an orange and blue range very similar to the way a painter would. Technically the process was a fairly traditional way of rendering. I used texture maps with painted photo textures and procedural shaders. To emphasize the painterly reference I used painted backgrounds.

Reference Images

A Rembrandt painting.

Images from - artist named in the lower part of the image


Maya renders with no background or compositing effects.

Below is a render with no background that I took into photoshop and painted over it. This served as a target to shoot for in the compositing stage.

Renders with compositing

Animated Sequence

Look 2

The second look referenced ink wash drawings and etchings. For this set of images I wanted to stylistically distance it from the first set as much as possible but still be faithful to the model. I wanted to achieve hard lines in the outline and interior objects with an ink washed brushed on effect for the shadow shapes. I spent a great deal of time researching an outline shader but was never able to write my own. The simplest method to get a line drawn effect in Maya without using paintFX is Mental Ray’s contour shader. For the shadows, I wanted broad brush strokes to follow the contours of the surface of the model. The brush strokes were a texture map applied to a surface shader that was not affected by light. The next pass was a shadow pass that was a hard lined black and white rendering. I used the shadow pass as an alpha channel for the brush strokes. They would only appear where there was a shadow shape. Using Nuke, I composited together the shadow shapes with the outline render on top of a static image of a canvas. The final result was a drawing moving on a still canvas.

A Rembrandt etching used as reference

Contour Render

Brushed Render

Shadow Render

Composited Renders

Animated Sequence

Look 3

For the final look I wanted to make something that was in between the last two looks. I chose a cell shaded look because it was colorful like my first rendering but was flat like the second look as opposed to volumetric. Additionally cell rendering has a long history in animation that is often overlooked as a rendering style that I was interested in studying. The process of setting up the rendering process was very similar to the previous look. I started with an outline pass. Next I rendered out a texture pass with a surface shader. The surface shader received light equally and consisted of simplified color image maps in cell shaded style. Another way of doing the color could have been to apply ramp shaders but I preferred image maps because of the greater control and specificity I could achieve. Finally for the shadows I used the same shader as I did for the last look but this time I used it as semi-transparent bluish tinted shadows rather than a mask. The final result was a successful cell shaded image.

Reference Images

The render process was very similar to the one above, in fact i reused some of the renders so I will not show the process images a second time. The only difference was the color layer:

Final Renders

Animated Sequence

This project was successful in giving me an insight into creating two specific non-photorealistic rendering styles. I feel very comfortable with Mental Ray’s contour shader and the project has given me ideas for future styles that I want to work on. An unintended and unexpected result was greater understanding of compositing fundamentals and working in Nuke. Being forced to solve alpha problems for the second look taught me about how images should be layered when compositing. Out of the three styles, my preference in animation is still the first. As a painter as well as a cg artist I am drawn to the stylized realism that I achieved in the first style but I am still interested in experimenting with new looks and styles.

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