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3D WORKSHOP:

Creating 3D contents using Blender 2.5

by Francois “Coyhoyt” Grassard

By placing each character's eyes on focal plane, your eyes don't have to move at each cut when you switch from one character to another. In this case, a 3D movie is as comfortable as a 2D movie because your eyes converge always (or at least, most of the time) at the same point, where is the place of the screen. By this way, we avoid all that eye gymnastics. You can even watch the movie without any glasses … all the characters won't have too much « blur » on their faces.

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When you shoot a 3D movie, in real life or in CG world, you have to choose if your cameras will be totally parallel or use vergence. Both methods exist and are heavily discussed by 3D professionals. Parallel shooting is usually more comfortable because eye muscles don't have to work a lot. But with a « Parallel Rig », we consider that the focal plane is pushed to infinite. So, objects can pop up out of the screen, but no one can go far « behind it ». When cameras use vergence, you can push objects far far away. But you have to adjust the rotation value of each cam really carefully. If it's too high, audience eyes will diverge. And your eyes never diverge in real life ! So, the final result of that is, once again, a big headache !

A.5) Optical issue in real life (why first 3D Movies was CGI): We just discussed rotation of camera rigs using vergence. But what is exactly a 3D camera rig ? In real life, a 3D camera rig is a set of tools that permit the placement of two cameras side by side and adjust the IPD and vergence between the cam. This kind of rig has to have a high degree of precision. All parameters changing on one cam have to be reported on the other cam. Focus, iris, zoom, gain, gamma .. and more. This synchronisation can be achieved by a mechanical or

When Bunny look at a close object, such as the apple, the vengeance angle is high

electronic process. Of course, the optical lens has to be the same for the two cameras. Many kinds of rigs exist. Just type « 3d camera rig » in Google image search engine to see dozen of different systems. Cameras are not always placed side by side. Because some kinds of camera are quite big ! Even if you placed the two cameras the closest you can, the distance between each optical center will be quite bigger than a human IPD. In this case, one cam can be placed like for a 2D shooting and the other one is placed upside down, filming the image reflected by a semi-transparent mirror. Once again, type « 3d mirror rig » in Google image to see different systems used. There are many problems you have to manage when you shoot with this kind of rig. For instance, the camera that shoots the image that passes through the semi-transparent mirror is darker than the one is directly reflected and shot by the second cam (about 1 stop darker).

Issue 28 | Jun 2010 - "Introduction to Blender 2.5"

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Profile for BlenderArt Magazine

BlenderArt Magazine Issue 28 Blender 2.5  

The Blender 2.5 series has been out for a while now, and while it still is under going a lot of changes and refinement, it is stable enough...

BlenderArt Magazine Issue 28 Blender 2.5  

The Blender 2.5 series has been out for a while now, and while it still is under going a lot of changes and refinement, it is stable enough...

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