Roto Artists trace the areas of live action frames where computer graphics will overlap or interact with live images. This creates clear areas (mattes) within the frame to allow all elements of the scene to be layered convincingly. This enables Compositors to combine all the various elements accurately. The role of Roto Artist exists more often on special effects work, within facility houses or on projects that combine live action and computer graphics. This process is called rotoscoping and originated in 2D animation when live action was traced as reference for movement or to establish where drawings needed to match to areas of live action. Rotoscoping is the first skill required by Compositors and continues to be part of a Compositor's role. On smaller projects, Compositors may do their own rotoscoping. If the camera is not moving within a shot, rotoscoping may involve only one frame; however, mattes will be needed if the CGI interacts with moving people, moving objects or moving background elements and, in these cases, mattes may be required for every frame. If the live action camera is moving, Roto Artists trace the relevant areas of every frame within that shot so that computer graphics can be combined accurately with the live action. In addition to rotoscoping, Roto Artists assist generally in the preparation of material for compositing, including such tasks as painting out wires and rigs; doing basic green and blue screen compositing; and grading live action plate
Paint/Prep Artists are briefed by Paint/Prep Leads or Comp Leads on the Paint Prep and wire/rig removal tasks for a particular shot or sequence. This includes Grain removal and grain matching, Generation of clean patches through collaging or clone painting on still frames, Image transformation, point/planar tracking, Basic matte generation through rotoscoping, luminance, chrominance and difference keying and many more Grain removal and grain matching Generation of clean patches through collaging or clone painting on still frames Image transformation, point/planar tracking Basic matte generation through rotoscoping, luminance, chrominance and difference keying Image filter types and effect on the image Camera tracking and image re-projection in 2.5D Warping and morphing Image stabilization Tracker marker removal Dustbusting, scratch removal and image restoration Colour correction Image Retiming Frame by frame paintinggeneration through rotoscoping, luminance, chrominance and difference keying and many more.
