Patent ID: 7398128

Claim:
A device for creating height-limited-area information for an empty space from a base plane based on three-dimensional shape information of a three-dimensional structure in which the empty space formed when plural sub-structures are combined, the device comprising: a base-plane-height determining unit that determines whether the base plane is formed with a plurality of planes with heights different by location; a base-plane determining unit that determines, when it is determined that the base plane is formed with the planes with heights different by location, whether to take the planes with different heights or a single plane as a basis; and a height-limited-area-information creating unit that creates, when it is determined to take the planes with different heights as the basis, the height-limited-area information by taking different planes for different locations as the basis, and when it is determined to take the single plane as the basis, creates the height-limited-area information by taking a single plane from among the planes with different heights as the basis.