Here are some examples of optical illusions. We’re going to create all of them. To begin with I’d like to tell you that it’s impossible to create an impossible object using 3D application (well, unless you’re working using real world settings and real perspectives, otherwise you can create anything). They doesn’t exist in real world, too. You can only fake the perspective and create a 2D illusion of a three-dimensional object. So, let’s see how it’s done on a few examples.
Step 1 – First Impossible Object
You can use your favourite 3D application for this tutorial. I believe that all of them will work well here. I used 3ds Max. First, create a three long boxes. Each one should have 1000×200mm. Place them like on the image below.
Move your view like me and create a camera (Ctrl/CMD + C).
Select your newly created camera and go to its settings. We have to turn on ‘Orthographic Projection’. Original perspective won’t work because it’s close to real one. It’s just hard to create an impossible object using standard perspective. Of course, it’s possible to use it but it would require cubes in different sizes and different distances between them. It’s much easier to use orthographic projection.
Select the target of your camera and change your view to Camera01 (press C on your keyboard). Now you’ll have to move your target very precisely until you get something like on the image below.
Step 5 – Impossible Object Render
Render your scene twice. First with everything like on the first image above and then delete a part of the cuboid that’s the closest to the camera (see the second image). Afterwards move both your renders to the Photoshop. Put each render and alpha map on top of each other and use an inverted alpha map (image below shows normal alpha map) to get rid of a part of SECOND render. Once you do it you’re done with this object!
Step 5 – Second Impossible Object
It works pretty much the same for the second optical illusion. It only seems that this one is a bit more complicated but in fact it’s not. The boxes are cubes with 200mm edge. Gaps in between them have 100mm. Once you create them establish your camera like me. Follow the previous step to render it and then create an illusion from two renders.
Step 6 – Third Impossible Object
This one is the most advanced although it works almost the same way with this exception that here you’ll have to use less stairs on two sides. If you used the same number everywhere you would have to place your camera over everything and that won’t create this kind of effect. Each stair has 300mm x 300mm x 50mm. This time you won’t have to render it twice.
Good luck with creating your own impossible shapes. Here are some other examples taken from Technionwebsite. Can you recreate them?
And again here are my examples: