This magnetic target provides an easy way to read the distance between two outside corners using a laser rangefinder or distance meter. The magnets clip to the sheetrock corner or nails near the desired corner, and the angle adjusts to ensure the proper measurement. Assembly is a difficult part of this project. The main beam MUST be printed LAST. The target plate needs to be assembled onto the partially finished main beam. First, print out the target plate, target frame, and angle beam. Then, print out the main beam, pausing the print and moving the print head away from the print above the level of the cylindrical hole in the main beam. Place the target plate into the now exposed slot with the two tabs facing towards the bottom of the print. I spaced the target plate off the print bed using some failed prints so the beam didn't come off the bed. Finish the print. The target plate should now be fully enclosed in the slot, and should slide back and forth fairly easily, and stay perpendicular to the main beam. Place the angle beam into the slot of the main beam, with the side with the thinnest wall facing towards the back of the main beam. Feed a piece of filament through the hole in the main beam and the hole in the angle beam, until about 1 mm sticks out the other side. Trim the ends to have about 1 mm of filament free floating. Take a second piece of filament, and feed it through the hole in the target plate, the slot in the angle plate, and the other target plate hole. Trim both sides to be within 1 mm of the target plate. Heat up your printer to the melting point of your plastic. Press the end of the filament into the hot end, and melt it down to the face of the main beam or target plate. Try to melt the filament all the way into the hole for best structural stability. Repeat for all four filament connections. Taking a knife, scrape off the excess plastic on all four joints. It is important to scrape the joints on the main beam down, as the target plate will slide past them. Cut your reflective target material to size. The target frame wraps around all the edges, so it is okay to oversize your material. Adhere the material, and carefully snap the target frame over the target plate. Take your choice of glue (end caps or sealed magnets will come in a later revision), and glue in 1 neodymium magnet to each beam. Push them as far in as they will go. To use, simply place on the corner, and adjust the angled leg to match the angle of the wall. If everything went well, the target plate should slide fairly well, and it should be easy to align the bracket to the wall. Then, point your laser rangefinder at the target plate, and take measurements. The retro-reflective material helps increase the return brightness of the laser, so longer distances in brighter conditions can be measured.