This study measures changes in teachers' attitudes, content knowledge, and spatial ability following a two-year visualization workshop experience. The workshop involved intensive, half-day sessions over three weeks for two consecutive summers, in which the participants worked with three-dimensional models and computer-generated images. No changes were observed in content knowledge and only a few significant changes in attitude were found. However, this study did find that throughout the workshop teachers' spatial abilities significantly increased with use and decreased with lack of use. (Contains 1 list, 4 tables and 4 notes.)