Expert: Amy - 1/16/2005

Question
I'm in grade 10.  Anyways, how do those 3D optical illusion work.  The ones that just look like patterns on the page, and then you kind of cross your eyes and you can see a 3D image made of the pattern... yeah, thanks for any help answering!

Answer
Hi Andrea,
this is how those optical illusions work. BTW their real name is random dot stereograms. They rely on our tricking our ability to see objects around us in 3D.

I think the best way of understanding them is to look at pictures and unfortunately I can't put them in these answers.so...here's my favourite websites on how random dot stereograms work.
None of these websites give all the information, so you'll have to read them all to get the best understanding.

Start off with how we see things in 3D

basic information on stereo (3D) vision
http://www.vision3d.com/stereo.html

how they make random dot stereograms
http://www.magiceye.com/faq.htm

how to look at random dot stereograms
http://www.vision3d.com/3views.html

happy reading!

Thanks,
Amy