On Monday, the California Supreme Court issued a thoughtful opinion that finally provides strong guidance on the use of animations in trial, affirming their proper place in supporting expert testimony. The decision People v. Duenas arose out of a criminal murder trial where the defendant objected to the use of a re-creation of the scene done by a biomechanical expert that purported to show the locations and direction of the defendant shooting a police officer. This post summarizes the opinion and gives three questions that attorneys should ask themselves when considering developing and using demonstrative evidence.