PLAY / Suzanne 3D Eye Trick ala Julian Beever

The 3D Optical Illusion Art of Julian Beever
Have you ever seen 3D floor art eye-illusion by Julian Beever? If you never seen one, you simply Google his name and find a lot of examples. It is pretty amazing and clever painting that distort your mind into thinking there is a 3D environment/artwork in front of you laying on a flat floor.

I have always been trying to do this eye-trick using 3D software, and not until tonight, I finally have a bit of time to doodle in Blender trying to create something like that.

Is it Camera Projection Mapping?
We know that the idea is to simply PROJECT some kind of 3D artwork (with clear perspective) into a plane. Simple enough right?

I actually search around, and of course it took me to Blender Guru's Andrew Price tutorial:
http://www.blenderguru.com/videos/camera-mapping/

That is cool tutorial he did, and probably I like to do something like that in near future. Anyhow, that kind of workflow seems to be too complicated for what we are trying to do. That is not really what we need.

Is it Projection Painting?
http://cgcookie.com/blender/2010/10/13/update-projection-painting-in-2-5/
Yes, this technique is pretty close to what we are trying to do. But that is also slightly more complicated that what we need as well.

Quick and Easy Texture Projection via Camera Background Image Projection
I figure this out actually by accident. Many cool features in Blender are seemed to be hidden, same with this one, the feature has already been inside Blender and it is pretty simple and automatic.

First of all, let's prepare our 3D artwork that will be the 3D optical illusion when viewed from certain angle. I made mine really super simple, just to proof the point, like below:

You do need 3D artwork that has some kind of clear perspective, otherwise we don't get much of the illusion happening.

Render that thing out as Square dimension, for simplicity:

Nothing fancy, I just use good old Blender Internal Render. You can use Cycle and create a more realistic 3D artwork. Go for it! You can have a really realistic illusion actually.

Next, is the actual technique to create the 3D illusion. We know that we want to project this artwork from certain angle into a simple flat planar mesh.

So, I open a new fresh Blender file, create a Planar polygon Mesh, do a quick UV texture on that plane and then project that texture artwork above from a certain angle, somewhere in which the plane of mesh is in line with the perspective of the picture.

Here is the steps:
1. Go to your Active Camera View
2. Activate "Background Images" for that Camera, setting should be something like below:

3. Match your polygon Plane into the artwork in term of perspective wise.

4. Next is the actual function to do projection. Simply click on "Apply Camera Image" function, just under Project Paint. You need to be in Texture Paint Mode.

You see how background image transfer directly to the flat plane in angle? That is what we are trying to do.

NOTE: The prerequisite to this is basic Blender Material, Texture, and Texture Painting setup. Few couple of steps in order for your mesh to be ready.

All working and good, you simply save your projected texture and you will get something like below:

Next thing, you just simply print it out on a piece of paper and then cut around the 3D part, just to have most of the effect happening.

TIPS
To have a really good perfect 3D effect, you can do everything in reverse. Start actually by taking reference picture of the environment, using the camera you will be taking photo (focal length matching the human eyes). You then match your 3D artwork into the environment. And then you do the Texture Projection from Camera thing.

Hope you like this effect!

Here is a video demo:

If you artwork is rendered more realistically  you will get a much better looking effect. Match it with environment lighting as well and you will really trick your friends!

UPDATE 2012.12.16:

Additional Notes Regarding "Preparing Mesh + Material + Texture" for "Projection". I mentioned above that you need some understanding on Blender Material + Texture + Painting before you are able to project anything into the texture. By request of "TheWarriorAbove" on YouTube, I will try to elaborate a little bit.

1. Your mesh needs to have proper UV layout.

2. Setup the Material and Texture:

3. You need to be in Texture Paint mode of your selected mesh. I usually work with the UV Layout preset. Anyways, you need to be in environment where you can Paint Texture on both flat UV and also on the 3D paint. I found that sometimes, under strange circumstances, Blender does not allow you to paint in 3D View. Occasionally happens, it is not a bug, just my understanding of the workflow that is not perfect. But 

4. Then you do the Texture Project thing from Active Camera View.

5. Texture Data is Dirty???

Ok, sometimes this is also happens. Texture on 3D View is correct, but does not update to UV yet. Usually I will hit TAB to go to UV mode, it seems to refresh the texture. So now you can save your projected image.

So, this is really the steps I did for simple Texture Projection from Active Camera in 3D View.

If still not clear, maybe I should do a YouTube video recording?

UPDATE 2012.12.24
This video tutorial is useful on how to setup UV and image for texture painting.
http://dipingo.org/TutVideos/CretureBumps/CretureBumps.html

UPDATE 2013.01.05
See also:
http://www.toxel.com/inspiration/2013/01/02/3d-illusion-drawings/
http://www.amusingplanet.com/2013/01/kurt-wenner-artist-who-invented-3d.html

UPDATE 2013.02.25:
More inspiration:
http://iskander1989.deviantart.com/