Google VR / Cardboard: How to customize rotation of left and right camera?

[wurstbrotrest]

Some days ago I asked how to adjust the distance of both cameras ( Gvr/Cardboard: Adjust position of left/right eye cameras manually - Questions & Answers - Unity Discussions ).

Now, the issue is the rotation: As you can see in the screenshot below, left eye and right eye are not identical. However, in my case - for viewing spherical and stereoscopic videos in Unity (which are already prepared for 3D) I need to have exactly the same camera position (translation and rotation) for each eye. Unfortunately it seems to me that the left camera and the right camera are rotated by default, although the Inspector of the left and right camera tell me the Y rotation would be 0. When I change the Y rotation in the Inspector for both the left and right camera and then press ‘Update Stereo cameras’ in the Main Camera´s Inspector, the X and Y rotations of the left and right cameras simply jump back to 0.

Why?

How can I tell Unity to accept my custom rotation?

Is there a UI / script solution?

[dolims]

It’s not actually rotation, but an asymmetric viewing frustum encoded in the projection matrix. You can see how this is set up here: Calculating Stereo Pairs

Although that site assumes time-sequential or red/blue stereo, rather than side-by-side stereo as in Cardboard (and most HMDs), the fundamentals are the same.

You do not actually want to remove this effect because this is literally what your eyes see looking through the lenses of a particular viewer.

In order to view a stereo picture or video, all you need to do is project each eye’s picture onto a sphere centered on that eye. Or, project both onto a very large (~500m or up) sphere centered on the head. If you do this, you don’t need to worry about the translation of the eyes, either.