...
1. Go to first frame | 2. Go one frame back | 3.Play backward | 4. Current frame | 5. Play forward | 6. Go one frame ahead | 7.Go to last frame | 8. Loop | 9. → Create OpenGL preview
...
1. Go to first frame | 2. Go one frame back | 3.Play backward | 4. Current frame | 5. Play forward | 6. Go one frame ahead | 7.Go to last frame | 8. Loop | 9. → Create OpenGL preview