The crime scene sketch may be a rough drawing made at the scene or it can be a polished document prepared for court using a computer-aided drawing (CAD) program. The sketch is an integral part of the crime scene investigation, invaluable in courtroom presentations, assists in understanding the locations and relationships that exist between items of evidence, and eliminates the detail and clutter that exist in a photograph. The sketch has two basic uses: to rebuild the crime scene, and for reconstruction of the crime. To be accepted in court, the sketch must meet the same legal requirements as any other piece of evidence. To ensure the admissibility of the sketch, the following notations should be put on the sketch: name of the person doing the original sketch, name of the person preparing the final sketch, case number, date of original sketch, location or address, and approximate scale. Several types of sketches are used for crime scene illustration. The most familiar and most used sketch is the overview, made as if one were looking down on the crime scene from above. What is drawn as a cross-section sketch is a vertical projection of the furniture and other items, which is useful to show the relative heights of items or show stains on the walls or bullet trajectories. Exploded sketches enhance an overview sketch by laying out the walls, which is useful when showing bullet holes or stains on the walls. Elevation sketches show the side of the building or a cross-section of the terrain to illustrate heights and landscape features. A perspective sketch is a representation of the third dimension on paper. The sketch artist must decide from which points to measure in recording the scene. Reference systems used include rectangular coordinates, baseline, triangulation, polar coordinates, and artificial reference points. The types of measurement include line of sight, contour, horizontal projection, and height. 10 figures, 3 references