The cameras page has more details about the common camera parameters. The additional attributes are shown below:

It is recommended that Lock Sampling Pattern is enabled in the Arnold Render Settings when using the vr_camera. This will avoid the sample pattern changing from one frame to the other, which can be distracting in VR.

 

Mode

 Stacked eye formats and cube map formats can sometimes have seams in the final immersive image. To avoid them:

  • use a 1x1 box filter (this is fine because a softer additional filter will be applied when the cube map is warped for display).
  • use resolutions that are multiples of the number of faces stacked in each direction. For instance, for a 3x2 cube map with one eye on top of the other, the vertical resolution should be a multiple of 4 and the horizontal resolution a multiple of 3.

Projection

Eye Separation

Eye to Neck

Top Merge Mode

Top Merge Angle

Bottom Merge Mode

Bottom Merge Angle

Merge Shader

 

 

Workflow

Pole Merging

While this method creates a very nice 3D effect for objects around the viewer, some nasty artifacts will appear at the top and bottom poles. This is because the camera offset makes it impossible for the rays to reach the top and bottom positions as you can see here:


Here you can see an example of how poles look like in this case:

 

 

We can fix these artifacts by smoothing the camera displacement when rays point upwards or downwards. This solution will remove the stereoscopic effect in the poles, but in practice, it is not very noticeable. In this case, the camera rays will look like this:

 


The pole merging will generate a result like this:

 

 

Different settings are provided to control this pole merging so it can be adjusted depending on the scene. First, top and bottom poles parameters are independent as they could have different requisites in your scene. For example, the pole merging at the floor might need to be very smooth if it has a lot of detail, but top merging can be more aggressive if it has a flat color, giving the upper hemisphere a more relevant stereoscopic effect. An aggressive merging at the top will look like this:

 


Pole Merging Workflow

To maximize the stereoscopic effect in the scene while avoiding poles artifacts, the top and bottom poles can be adjusted independently to better suit the specifics of a scene.

The artifacts at the poles can be of two different kinds:

Distortion Artifacts:

The single image you see from an eye has some deformations at the poles. Perpendicular lines do not meet at 90 degrees. These artifacts tend to appear as you increase the Merge Angle. Some examples:

 

Stereoscopic Artifacts:

When you take a look at a single eye image, you might notice a different distortion, but when you see both right and left images, you will notice a circular wave on the pole. Here is an example:

Right eye / Left eye

 

 

 

Example Workflow: Mery Video

Making this video was quite simple. The following steps were taken to create it:

  • Add a generic VR camera and adjust it with the correct parameters.
  • Fix the scene so that you can look in any direction. Behind the windows, some images were added to simulate the outdoor as well as a couple of columns to hide some lighting artifacts that didn’t appear in the original scene camera.
  • A single frame with the credits was rendered and added back to the final video inside Nuke.