For design and art enthusiasts who seek to enhance their skills through instructional videos, following drawing instructions while practicing can be challenging. STIVi presents perspective drawing demonstrations and commentary of prerecorded instructional videos as interactive drawing tutorials that students can navigate and explore at their own pace. Our approach involves a semi-automatic pipeline to assist instructors in creating STIVi content by extracting pen strokes from video frames and aligning them with the accompanying audio commentary. Thanks to this structured data, students can navigate through transcript and in-video drawing, refer to provided highlights in both modalities to guide their navigation, and explore variations of the drawing demonstration to understand fundamental principles. We evaluated STIVi's interactive tutorials against a regular video player. We observed that our interface supports non-linear learning styles by providing students alternative paths for following and understanding drawing instructions.