Usually when people talk about 3D illusions they mean a three dimensional image hidden within a two dimensional abstract pattern. 3D illusions are an extremely highly developed type of stereogram. To create this kind of image one has to combine the use of technology and artistic talent.

The first step is to create any 3D form. The only rule: it is supposed to be a true 3D model, which can be rotated and edited which can be achieved by any 3D software, It should provide the required flexibility for the picture. Without advanced graphics developing software in the hands of an experienced designer, you will hardly get the chance of a good outcome.

The gray scale rendering of the model becomes the source for the hidden image. The next step is to create a 2D pattern which will work as a visible front pattern to camouflage the hidden 3D picture.

The 2D pattern is the main thing in creating the overall look and feel of the picture. What kind of images is it usually compound? Anything you can think of; some big corporations ask designers to use company logos and colors to create something really special, and, of course, other design elements for that visible 2D pattern are also widely used.

2D patterns are usually unique and almost never repeated.

The third step is the computer program that takes the grayscale source image and mixes it with the 2D pattern to encode the hidden image.

In instructions for these amusing pictures they usually say that in order to view a 3-D image, we simply are supposed to stare at it until the image starts to take shape. But not all the people can recognize the hidden 3D shape at once.

To improve your 3D vision, you must look actually through the stereogram and a little bit into the distance. The problem is there's a solid object in the way, let’s say a computer monitor. How do you look through a solid object?

Suggestion: imagine you are looking through a window, but still try to notice and keep within your sight some closer object, your thumb, for example.