Invert Z-Depth ( Back-Face Culling ) in Blender 2.57

These are some of the first things that I created to start off in Blender and how I made them.

A Cube Inside of Another Cube

My first few creations were inspired by an artist on Deviantart.com - Cezkid.  He makes 3D pixelated 8-bit video game characters (voxel models) that I found to be pretty novel - Cezkid Voxel Characters. He uses Google SketchUp not Blender.

cube inside of another cube with Invert Z Depth enabled

So at first glance, this cube looks quite unimpressive. You'd think it was just a cube with a big blue border around it, but it's not. And it wasn't that easy to figure out how to execute.  I asked Cezkid for some leads and he mentioned "back-face culling". Well it was a lead, but it did me little good because Blender doesn't have an option named back-face culling or anything similar.  Also, this was my first model, and I had little to no idea how to determine the visibility of a polygon or face.  After many hours of Googleing and tweaking, I happened to stumble upon the Invert Z Depth property (Zinvert in earlier versions) by accident - success.

Brief Invert Z Depth Explanation:
These are two cubes- a small one ( solid grey material with Recieve Shadows and Cast Shadows turned off and Z Transparency turned on), and a bigger blue one ( solid blue material with Shadeless and Invert Z Depth property turned on).  This creates a mesh (the big cube) that has transparent faces when they point to the camera.  This also works on two-sided faces in case anyone's wondering. Read on to see exactly how I did it.


Invert Z Depth Tutorial:
You don't need an actual mouse with a wheel for this tutorial. A touch pad will suffice.

• Open a new Blender project
• Right click on the cube in the 3D View to select it.

  

  selected cube object

• Go to Properties Panel (SHFT+F7) and select Material



Materials icon in Properties panel

• Scroll down to Shading and check Shadeless



set Shading to Shadeless

• Scroll down to Options and check Invert Z Depth



Inver Z Depth

• Place the cursor in the 3D View and press the ZKey to show the cube in Mesh mode.
• Be sure the cube is selected and press SHFT+DKey to duplicate the cube. 
• Press ESC (otherwise the duplicated cube will move around)
• Press SKey > type the number .5 > press ENTER (this scales a cube down to half size)



scaled cube inside duplicate in mesh mode

• Now be sure that the smaller cube is selected and go to the top of its Material panel.
• Remove the Material by pressing the minus-looking button.



Remove material and add a new one

• Press the + New button that pops up.
• Check the Transparency option and enable Z Transparency (THIS IS IMPORTANT)



enable Z Transparency in the smaller cube

• Scroll down to Shadow and un-check Recieve.



un-check Recieve in Shadows option

• Press F12 to render!

If everything went smoothly, you should see this:

 Hope this may help anyone who may be looking for something similar. I have no idea how this will hold up under other scenarios or circumstances, but it worked for this example.

Other Objects
Here are two other objects that I created with the same concept.