CRISTAL: Dimensioning Process The VCAD dimensioning process begins with locating and marking the control points on the reference stadia in the digital image. This establishes the basis for the computation of a dimensional grid overlay. Each of these control points is located using a mouse cursor to indicate the reference targets on the stadia. The marking of the control points enables the VCAD software to compute the planar grid construct that is used to calculate dimensions. The computed grid consists of three planes, each of which can be used as a dimensional field: left of the stadia, right of the stadia, and the ground plane. Because the computed grid is a three dimensional construct that can be moved and rotated, the stadia generated grid needs only to be defined once for each image in the database. Once the planar grid is constructed and adjusted to a known baseline dimension, dimensions can be extracted from the image by using the mouse cursor to mark the two end points of a desired vector that lie on one of the defined planar surfaces in the image. The software computes the actual distance between the two points, as well as the absolute horizontal (X) and vertical (Y) differentials. Component parts of a building image that do not coincide with any of the planes can be dimensioned by adjusting the location or orientation of the grid to coincide with the appropriate planar surface. In order to accommodate this planar variety in any given image, the dimensional grid can be manipulated in three basic ways: 1... moving the grid along an X,Y,Z axis to align one of the grid planes with a surface in the image that contains the vector to be measured. 2... rotating the grid about an X,Y,Z axis to align one of the grid planes with a surface in the image that contains the vector to be measured. 3... extending the grid to allow the dimensional analysis of elements that are located outside of the geometrical construct generated by the original orientation of the stadia. CRISTAL: Dimensional Analysis CRISTAL: Extracting Dimensions