Stereo Mix Material Node

Stereo Mix is a niche node, used exclusively for stereoscopic rendering. It lets a 3D object have a different shader per eye - an unusual setup but sometimes needed for specific VR or anaglyph effects.

The official documentation notes that it is "often used to output the left and right eye from the 3D Render".

• Effects Library: Tools > 3D > Material > Stereo Mix
• Quick add: right-click in the Node Editor → Add Tool > 3D > Material > Stereo Mix

• LeftMaterial (orange) - required. Material used to render the left eye. 2D images are converted into a diffuse texture with the basic material.
• RightMaterial (green) - required. Material used for the right eye.

Output = always a 3D material you can use on any Shape 3D/Cube 3D/etc., regardless of the type of the inputs.

Red Blinn ──→ LeftMaterial
Blue Blinn ──→ RightMaterial
          → Stereo Mix → Shape 3D → Merge 3D ← Stereo Camera → Renderer 3D

It needs a stereoscopic render to make sense - a mono scene will always use the same material (depending on the Eye selected on the Renderer or Camera).

Swap

Swaps the two inputs: what was on LeftMaterial becomes the right eye and vice versa. Handy to fix an accidental assignment without reconnecting.

Material ID

Numeric identifier for the Material ID AOV. When enabled in the Renderer 3D, it extracts a mask of the resulting material.

• Classic red/cyan anaglyph - LeftMaterial = Blinn with a dominant red channel, RightMaterial = Blinn with dominant green/blue channels. The combination is visible with traditional anaglyph glasses.
• VR with differential detail - one eye sees a more detailed material, the other a simplified one → render savings for barely perceived areas (rare case).
• Artistic stereo effect - a color difference between the eyes for a "parallel dimension" or dreamlike look.
• Stereo test / debug - color the left eye red and the right eye blue to quickly check that the stereo works visually.
• Logical left/right split - if the downstream pipeline must handle the two eyes differently, Stereo Mix is the point where they diverge.

• Very specialized use - for standard stereo rendering where both eyes see the same material (just with different cameras), this node is not needed.
• Quick swap - if the stereo image looks inverted (a "warped" feeling in VR), try Swap before reconnecting the inputs.
• Material ID - even though the node is niche, assigning an ID is still useful for downstream compositing.
• For most Fusion 3D/VR projects, the Renderer 3D and the Spherical Camera (or a Camera 3D with stereo settings) are enough. Stereo Mix is only needed for materials that are specifically different per eye.