A generation device (10) includes: a 3D reconstruction unit (12) that reconstructs an original three-dimensional
image based on a plurality of images and a plurality of depth images, and acquires information indicating a position, a posture, a shape, and an appearance of a mapping target object that is a target of mapping to a digital space, and position information and posture information of an imaging device that has captured the image and the depth image; a labeling unit (13) that acquires a plurality of two-dimensional images in which labels or categories are associated with all pixels in an
image based on the plurality of images; an
estimation unit (14) that estimates a material and
mass of the mapping target
object based on the plurality of two-dimensional images and the position information and the posture information of the imaging device; and a generation unit (16) that integrates the information indicating a position, a posture, a shape, and an appearance of the mapping target object, and the information indicating the material and
mass of the mapping target object, and generates digital twin data including position information, posture information, shape information, appearance information, material information, and
mass information of the mapping target object.