We provide a few interaction clips to illustrate the use of STIVi on various videos we processed. Each clip corresponds to a different video. By clip, we refer to the file contained in this folder. By video, we refer to the commented sequence recorded by the instructors, taken as input by our system. 

- "3pointperspective.mp4": the video (excerpt from a Youtube video [9]) explains how to draw in three-point perspective. The clip shows a part of the highlighted video then the use of sketch preview to navigate through high level step, also aligned with the chapters. 

- "cube_2.mp4": the video explains the drawing of a cube. It is shot by another instructor than the one used in the user study. The clip shows the video with highlight. Clicking on links accelerate the pace of the video. The circular widgets are used to inspect vanishing point placement. 

- "division_multiplication.mp4": the video (excerpt from a Youtube video, https://www.youtube.com/watch?v=KRuQhy0l_4o) explains division and multiplication techniques using diagonals of a plane. The clip shows a part of the highlighted video and the use of circular widgets to see the impact of foreshortening on the duplicated plane.  

- "perspective.mp4": the video (excerpt from a MOOC video, https://vimeo.com/214849073/549bbe3361) explains how to draw a cube in perspective. The clip shows the use of the sketch preview to investigate the order in which elements are drawn, then to select the two front planes. The circular widget is used to modify the perspective. Then a few navigations through thumbnail and links are showcased. We play the video to show highlights then inspect the variation of angle between the lines using the circular widgets. 

- "perspective_1point.mp4": the video explains the concept of vanishing point in the context of one-point perspective. The clip shows navigation through sketch preview then a short excerpt of the video with highlights. A thumbnail navigation is used to accelerate the pace of the video. 

- "perspective_2point.mp4": the video explains the impact of the placement of vanishing points in the context of two-point perspective. In the clip, sketch preview is used to quickly go through the video and the different position of the box compared to the vanishing points. 

- "planes.mp4": the video (excerpt from a Youtube video [35]) explains how to build a rectangular prism with a plane structure, which will be useful to draw various vehicle shapes. The clip shows a part of the highlighted video and the use of circular widgets to modify the aspect of planes. Sketch preview is used to navigate through planes. 

