- Ray Tuck
This simulates the effects of parallax when measuring length.
- The blue dot represents the position of the observers eye. Its position may be adjusted using the Eye position slider.
- The Green bar is the object being measured - adjust its true length using the object length slider.
- The Object position slider adjusts the separation between the object and the scale.
- Check Show perpendicular to show the ideal sight line at right angles to the rule.
- Check Show error angle to show the deviation of a sight line from the perpendicular