Spatial ability contributes to performance in science, technology, engineering and mathematics (STEM). Spatial skills and creativity are required for engineering studies. Low spatial abilities can lead to the dropout of students’ university studies. In this study the Spatial Ability Extra Tasks (SAET) was developed to evaluate engineering students’ complex spatial abilities. A total of 93 first-year engineering students from University of Debrecen Faculty of Engineering and Sharif University of Technology in Tehran participated, with regard to final mathematical exam and their gender, participated in the study. SAET measures parts of spatial abilities: mental cutting and mental rotation and creativity. Analysis of the findings suggested that SAET is valid and reliable. The separate tests results have been statistically evaluated and conclusions were formulated. We used Structural Equation Modeling analysis. We separate two types of tasks by SAET which are Polyhedron part and Curved Surface part. According to obtained data, accomplished the results: students of University of Debrecen are more successful at Curved Surfaces. In addition students of Sharif University are more successful at Polyhedrons. The square cross section was found by most student in both countries in Polyhedrons. It is remarkable that first-year engineering students of Tehran are more successful at Polyhedrons by pentagon, hexagon and parallelogram solution; and students of Debrecen are more successful by square and rectangle solution. Students of Debrecen are more successful at Curved Surfaces to find circle solution of cylinder, cone and sphere; students of Tehran are more successful by finding parabola solution of cone.