Talk:Kassadin/SkinsTrivia/@comment-24035110-20140130103037/@comment-1330314-20141017025911

From my extremely small knowledge of graphic design, I think the animation technique is something called a mask: a mask is an area-specific alteraction to a larger surface, and here Kassadin's blade is actually a much larger surface that you cannot see, bar the blade-shaped area made visible by the mask, hence the mostly static background pattern when his blade moves around. His ult would apply the same mask to briefly reveal that same background surface. This may sound confusing, but an analogy for the technique would be cutting a hole in a piece of paper, and looking at a drawing or a painting through that bit of paper while moving it around.