The Advanced Art of Stop-Motion Animation: Visual Effects - Part 2

In the latest excerpt from The Advanced Art of Stop-Motion Animation, Ken A. Priebe discusses the use of bluescreen and advanced compositing.
Posted In | Magazines: AnimationWorld | Site Categories: Education and Training, Stop-Motion
Image
[Figure 9.45] 3D environment with some background elements for
the sky.
[Figure 9.46] Illustration by Henrique Moser of the background and
foreground elements and cameras in the 3D environment.
[Figure 9.47] Example of a matte created to mask out the passing
foreground disc from the cliff, before color-correcting. (Courtesy of
Lucas Wareing and Henrique Moser.)

The matte painting itself, originally done in Photoshop, had its various middle-ground and background elements of mountains and clouds separated onto different layers (Figure 9.45). These split-up layers of the painting were projected onto separate cards in the 3D environment to create a parallax effect as the camera moved through the set. This basically means that there is a change of perspective in the background elements that creates more depth and simulates how it would look in a 3D space, as opposed to just one static background element that stays the same through the whole shot. In the 3D environment, there was one camera that tilted upward and moved down to match the physical camera move, and another camera that was locked down and acted as a projector for the various foreground and background elements in the virtual set (Figure 9.46).

The plants and various bits of foliage were keyed out through a combination of various keying techniques to extract mattes from them. Also, in front of the virtual 3D version of the camera move, certain elements that existed in physical space on the stop-motion set were projected onto 3D cards in the exact places they appeared within the set. Certain things like the branches, plants, and cliffs would go through various stages of movement and overlap with each other as the camera moved past them, so on certain frames, sections of these set pieces had to be matted out and projected to all match together. Many things in the set needed to be painted out, including the black disc that was animated throughout the set to line up with the moving sunlight and cover it up. The projection of mattes onto the 3D cards helped in the particular frames where the disc passed in front of the cliff, for example. To cover up the disc, a section of the cliff from another frame could be matted out and placed in the space it needed to be (Figure 9.47). The color grading would also need to be manipulated to blend in with the rest of the shot since the light changes throughout the whole scene.

Image
[Figure 9.48] Highlights created by the lighting in the frame are
keyed out.
[Figure 9.49] The background is separated from the foreground
[Figure 9.50] The keyed highlights are manipulated and then layered
over the original footage. (Courtesy of Lucas Wareing and Henrique
Moser.)

In addition to the basic process of compositing and removing the various elements from the original footage so that the composited background could show through, other subtle effects were added to enhance the atmosphere. One example was to enhance and exaggerate the highlights created by the sunlight at the end of the shot. This was done by keying out the bright highlights in the frame itself (Figure 9.48) and then separating the foreground and background into an alpha channel matte (Figure 9.49). The highlight shapes were blurred and given a warmer color tone, which could then be layered over the original shot to exaggerate the highlights, making them brighter and softer in the rim of light along Charlie’s body and next to his shadow on the ground (Figure 9.50).

Many other effects and subtle details were executed within the advanced production method of completing this shot, all coming together to bring to the audience a beautiful and unique approach to the art of stop-motion filmmaking. Check out the movie called Ava Footage.mov on the CD to see the original footage from the stop-motion set and breakdowns created by Henrique Moser of a few steps taken to create the final shot.

Ken A. Priebe has a BFA from University of Michigan and a classical animation certificate from Vancouver Institute of Media Arts (VanArts). He teaches stop-motion animation courses at VanArts and the Academy of Art University Cybercampus and has worked as a 2D animator on several games and short films for Thunderbean Animation, Bigfott Studios, and his own independent projects. Ken has participated as a speaker and volunteer for the Vancouver ACM SIGGRAPH Chapter and is founder of the Breath of Life Animation Festival, an annual outreach event of animation workshops for children and their families. He is also a filmmaker, writer, puppeteer, animation historian, and author of the book The Art of Stop-Motion Animation. Ken lives near Vancouver, BC, with his graphic-artist wife Janet and their two children, Ariel and Xander.







Comments


I found just what I was needed, and it was entreatiinng!

Roxy (not verified) | Sat, 07/16/2011 - 09:51 | Permalink

Got it! Thanks a lot again for heplnig me out!

Unity (not verified) | Fri, 07/15/2011 - 19:42 | Permalink

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