Validating the Sun System in 3ds Max for Recreating Shadows

<div class="section abstract"><div class="htmlview paragraph">Shadow positions can be useful in determining the time of day that a photograph was taken and determining the position, size, and orientation of an object casting a shadow in a scene. Astronomical equations can predict the location of the sun relative to the earth, and therefore the position of shadows cast by objects, based on the location’s latitude and longitude as well as the date and time. 3D computer software includes these calculations as a part of their built-in sun systems.</div><div class="htmlview paragraph">In this paper, the authors examine the sun system in the 3D modeling software 3ds Max to determine its accuracy for use in accident reconstruction. A parking lot was scanned using a FARO LiDAR scanner to create a point cloud of the environment. A camera was then set up on a tripod at the environment, and photographs were taken at various times throughout the day from the same location. This environment was 3D modeled in 3ds Max based on the point cloud, and the sun system in 3ds Max was configured using the date and time of the photographs. Photogrammetry techniques were used to align undistorted photographs to the 3D environment, and rendered images were compared to the photographs. The results show that the 3ds Max sun system recreates the sun's position adequately, making it a reliable tool for accurately determining shadow locations and dimensions.</div></div>