This article presents exact algorithm for calculation "length of tangent" to quadric surface based on results of measurement tangent directions to shell object. The considerations are mainly about one-sheet hyperboloid shape. The considerations made for the objects in the shape of hyperboloid of one sheet. Using the algorithm can calculate the location and shape, but also the parameters of the shell, which compared to previously used methods, allows for better precision than that calculated on the basis of previously existing algorithms. Modification of the algorithm presented allows to increase the accuracy of the final results, using the proposed method of measurement. This solution saves money and time. ...