Dimension uses analytical equations which describe the physical model of how the image is formed, i.e., light essentially travels in a straight line from the object, through the lens, and onto the film or array. The use of a physical model is the most accurate way to make measurements in an image. The analytical equations include parameters that are referred to collectively as the camera model. The only part of the system that does not use the camera model to make measurements is the Direct Scaling function. You will not be allowed to create annotations or perform any of the measurement functions unless the image is part of a project.
Dimension is organized around the concept of a project.
When creating a new project, the user will be asked to enter the project name. The term camera model refers to the set of parameters that define the geometric relationship between the camera and the object, as well as certain aspects of the camera itself. These parameters describe where the camera is and which direction it is pointing relative to the object. The lens is described by the its focal length. Other information about the lens is included in the form of lens distortion parameters.