Although students are highly interested in astronomy, they have difficulty understanding the content. Previous studies have pointed out that one of the reasons for this is that students doesn't retain the "ability to shift their viewpoints". In this study, we developed 3D teaching materials that show the changes in the shape of Venus as it orbits, because we thought it was necessary to develop the "ability to shift the viewpoint" to correctly understand the shape of Venus that changes with its orbital motion. As a result of learning activities using the developed 3D teaching materials, it was confirmed that certain effects were obtained in understanding the changes in the shape of Venus as seen from the Earth.