A method and system for generating three-dimensional antenna patterns from two-dimensional cross sections. The method involves an estimate (1006), on a given vertical plane, obtained by rotating a gain value (1010) from the front of the vertical pattern using the horizontal pattern (1004) as a weight; a second estimate, which could be on a separate vertical plane, obtained by rotating a gain value (1014) from the back of the vertical pattern, and a final estimate (1206) obtained by connecting the first two estimates across their respective planes. The invention yields smooth reasonable surfaces (1704) that satisfy the vertical and horizontal boundary conditions, exhibits no mathematical artifacts, and improves the accuracy of propagation calculations of radio frequency signals. The method is implemented in a software system (1812) that provides interactive analysis and visualization capabilities for antenna patterns in three dimensions.