Jian Feng & Qing Sun: Visual Illusions

Published on December 13th, 2011 by Jian Feng. Filed under Digital Media, Film & Movies, Video Games

This is a joint project by Jian Feng and Qing Sun.

We carried out a survey about visual illusions based on the game we are making. We compiled our work to a voice video. Below is the link to the video.


We also attached the script for the video as a reference.

Thank you very much!


Visual Illusions

Hello this is Jian Feng and Qing Sun.

Out final project is about “visual illusions” in games, especially illusions on smoothness and speed.

For this purpose we created ten video clips from the game we are making. The game is called “STEER ‘n’ SLIDE”, in which the player is sliding in an endless tunnel. Based on the video clips we carried out a survey to see how it delivers an illusion of smoothness and speed. For all of the control experiments, the tunnel is moving at the same speed, and the tunnel’s geometries and meshes are exactly the same. The only thing we modified is the tunnel’s texture in each of the ten video clips.

Up to now 63 people have taken the survey and below shows the survey results.

In the first three videos we do survey about how to create a smooth and convenient illusion.
1. We add a triangle at each of the four corners of the texture, which cover the sharp angle between the mesh polygons. This works well to create a smoother illusion with the same polygonal geometry.

2. Sometimes when the avatar or the environment is spinning, the player may feel dizzy. This test shows that concentrating on objects far away could help reduce the dizzy feeling.

3. We also want to know if smoothness helps. Apparently, for most people, the smoothed round tunnel feels much better than the polygonal tunnel.

In the other videos we focus on the sense of speed.
4. In this video clip the parallel lines in the right tunnel are stronger and darker than those in the left one, which actually decrease the sense of speed according to the result. From this we assume that the perpendicular lines are more significant to generate the sense of speed, and since the stronger parallel lines relatively weaken the visual effect of the perpendicular lines, the right tunnel seems to move slower. We prove our assumption in the next few clips.

5. So in the fifth clip we strengthened the perpendicular lines instead, and the result shows that more people agree that the one with stronger perpendicular lines is moving faster. However, there are still 32% of people thinking in the other way. So this might not be the most important factor.

6. Then what about density? We double the density of the parallel lines. Yeah, more people think the tunnel with more parallel lines moves faster. But again, we could only cheat 43% people’s eyes.

7. Well, if we increase the density of the perpendicular lines, nearly all of the responses agree it is faster. So with more perpendicular references, it could easily make us feel we are moving faster than we actually do.

8. Are there other factors? We attached a relatively realistic texture to the meshes. To our disappointment, people still think the simpler tunnel moves faster. We found out this is because the simpler texture has a relatively blurry effect, which may help increase the sense of speed.

9. So we added a blurry effect to the same texture and it works! Most people agree that the blurred one is at higher speed. In addition, because the left tunnel, which should be without any blur, is still moving with some “resolution loss” blurry effect since we uploaded it to a website(Vimeo), we believe that the difference would be much apparent if the tester watched the original video.

10. And, of course, we still remember that we were shown two car racing videos where the cameras were located above or at the bottom of the car at class. So we also carried out a survey about the camera’s location. From the responses, apparently, the lower the camera is, the faster we feel.

Conclusion and Examples
<span style=%


Copyright © 2019 visualinquiry