Methods and systems for graphically creating a representation of an
anatomical structure, such as a heart, is provided. The distal end of an
elongated probe is moved within the anatomical structure, and geometric
shapes are defined within a coordinate system. By defining geometric
shapes, such as spheres or circles, as the distal probe end is moved
within the anatomical structure, the cavity within the anatomical
structure can be represented. A representation of at least a portion of
the anatomical structure can be graphically generated based on the
geometric shapes, e.g., by determining a union of the geometric shapes
and conforming the graphical representation around the union of the
shapes. In the case of a heart, the union of the shapes will generally
represent the blood volume within the heart, so that the graphical
anatomical representation (which in this case will be a graphical
representation of the endocardial surface of the heart) can be accurately
conformed around the representative blood volume.