Explanation
Occlusion is the phenomenon where objects -- virtual or real -- correctly hide one another based on their relative positions. In mixed reality, proper occlusion means a virtual character walking behind your real table disappears behind it, just as it would in the physical world. Without occlusion, virtual objects appear to "float" on top of everything, breaking the illusion immediately.
Real-world example
A virtual character passing behind your real table and disappearing from view.
Practical applications
- Real/virtual fusion realism: virtual objects respect the spatial logic of the real world
- AR/MR credibility: without occlusion, virtual objects "float" unrealistically
- Coherent interactions: a virtual object can be hidden by your real hand
- Enhanced immersion: the brain accepts virtual content that follows real-world rules
Types of occlusion
Virtual hides virtual
- A 3D object in front of another hides it
- Standard behavior in 3D/VR
- Handled automatically by 3D engines
Example: A virtual wall hiding what is behind it
Real hides virtual (the AR/MR challenge)
- Your real hand must hide a virtual object
- Requires 3D reconstruction of the real environment
- Technically complex but improving rapidly
Example: A virtual character passing behind your real sofa
VR scenario
In mixed reality, a virtual cat plays in your living room. When it runs behind the coffee table, it correctly disappears behind it. Without this occlusion, it would "pass through" the table, instantly breaking the illusion.
Why it matters in professional VR
- Occlusion is crucial for mixed reality to be believable
- A quality benchmark for MR headsets: Quest 3 and Vision Pro handle occlusion well
- Without good occlusion, AR/MR experiences remain a "gimmick" rather than convincing