The acquisition of 3D modeling competencies is becoming increasingly critical within the domain of design education. Nonetheless, conventional teaching methodologies frequently fall short in cultivating the advanced cognitive capabilities demanded in the current AI landscape. This research examines the effects of employing the 6E instructional model--comprising Engage, Explore, Explain, Elaborate, Engineer, and Evaluate--on metacognitive behaviors within a 3D modeling curriculum. Employing a quasi-experimental design, the study engaged 40 university students from both IT and non-IT backgrounds in a 9-h instructional course utilizing Rhino software for 3D modeling. Metacognitive behaviors were evaluated through lag sequential analysis, coding procedures, and semi-structured interviews. The results indicated that metacognitive knowledge behaviors were most frequently observed, with notable progression identified between knowledge and skill-related behaviors. Students with IT backgrounds exhibited superior competency in integrating theoretical knowledge with practical application, whereas those from non-IT backgrounds more frequently utilized collaborative problem-solving strategies. The role of teacher guidance was found to be instrumental in augmenting students' comprehension and application of modeling concepts. The study advocates for the integration of metacognitive prompts within instructional design to enhance learning outcomes and promote autonomous problem-solving capabilities. This research contributes empirical evidence aimed at advancing 3D modeling education and offers valuable insights for educators striving to formulate effective instructional strategies amid the swift advancements in technology.