<![CDATA[Background: This study is motivated by limited understanding of building structure concepts among vocational high school students, resulting from limited instructional media and the continued dominance of conventional teaching methods. This study aims to examine the effectiveness of the Learning by Doing approach, supported by physical mock-ups of rubble stone foundation and footplate structures, in improving conceptual understanding and learning motivation. Methods: This study employed a one-group pretest-posttest design involving 8 eleventh-grade students from the DPIB program at Vocational High School (SMK) Sunan Drajat Lamongan, selected through purposive sampling. Data were collected through essay tests, observation, and questionnaires, and were then analyzed both quantitatively (paired t-test, Cohen's d) and qualitatively. Results: The results showed an increase in the mean score from 26.63 to 35.50 (on a 0 – 60 scale), with an effect size (Cohen's d) of 0.97, classified as large. Although the statistical increase was not significant (p = 0.073), the large effect size indicates a meaningful practical effect despite the small sample size. Qualitative analysis revealed a clear improvement in conceptual understanding, such as students' ability to explain the function and mechanism of basic structural components more systematically. Affectively, most students (87.5%) reported that the mock-ups were very helpful in visualizing the concepts, and all students reported increased learning motivation. Conclusion: This model-based learning approach has the potential to serve as a cognitive bridge linking theory and practice and to contribute to increased student motivation. This medium is a promising alternative learning strategy, especially for vocational schools with limited facilities.]]>
