CompuServe Messages

Hi William, Seconding the comments of the other participants, and also: — I saw a very effective use of opacity mapping by Alan Henry in Phil Shaddock's "3D Modeling Lab" [Waite Group Press, 1994]. He modeled a closeup of a honeybee in Imagine/PC, and the body had some fairly convincing hair. The body was texture-mapped to give the proper appearance for most of the bee. But the silhouettes, as you point out, were too smooth. Alan solved this by duplicating the body and scaling it up just a smidgin. This was given a sparse opacity map… the only visible areas were hairlike strands. This gave the bee a "hairy" silhouette… clever solution. — As David points out, the Xaos filters excel at this kind of "brushing engine" work. While you could do this during post within Painter or DeBabelizer, I don't think it would work for animations — the particles would need to refer to the object's 3D coordinates in order to look "right" during movement. Posting in 2D would make the hairs jump around and twitch with each frame. Real pretty for stills, though… have you seen Auguste Raffael's "Hairy Eye" on the Xaos postcards? — Which brings up procedural pixel-based displacement. Sorry to say, but I haven't seen anyone hit this on personal computers yet, at least not for something as involved as hair. I'm not sure how Rhythm & Hues did the polar bears — I sure as heck hope they didn't describe geometry for it! — but suspect that it was some sort of structured particle system, like that explored in Bill Reeve's 1985 SIGGRAPH paper describing Pixar's "Adventures of Andre and Wally B." Sort of a wash, Bill, but perhaps that opacity-mapping technique may, ah, provide a hair-raising experience…. <g> Regards, John Dowdell Macromedia Tech Support