Abstract: A tracing tool for marking an outline of an irregular surface onto a sheet of material so that the sheet of material can be cut along such outline to fit snugly against the irregular surface, such tool including a case having a cavity in communication with an opening in the case, such case enclosing a piston having a shaft linearly extending therefrom through the case opening with a spring biasing the piston toward the case opening, and a marking device passing through a marking hole in the shaft which marking hole is perpendicular to the plane of the sheet of material. The shaft at its end includes a horizontally disposed guide roller for facilitating sideways rolling of the shaft along the irregular surface while the shaft moves back and forth perpendicularly to the irregular surface which movement moves the piston in the cavity as the marking device marks the outline of the irregular surface on the sheet of material.