# Render blocks and occlusion factor

**The occlusion factor**

The concept of occlusion factor is directly linked to the concept of the Zone Of View.\
Simply put, it represents the quantity of objects that are hidden from the center of the Zone of View, but visible from another location in the Zone Of View.<br>

For instance, in a scene with rows of standing dominos, a lot of those might be invisible from the center of the ZOV because they are occluded by the first domino, but still, they can be seen from other parts of the ZOV.\
The same will happen in a forest with leaves and trunks.\
All those "occluded" objects must still be rendered for V-Nova PresenZ since they can be seen from the ZOV. In that case, we have a high occlusion factor.\
\
Now imagine the Zone Of View is in the middle of a big sphere made of concrete. In that extreme case, there is no object occluded; everything that is visible from the whole ZOV is also visible from the center of the ZOV, and the occlusion factor will be null.\
\
**The render blocks**\
\
The render phase breaks down the render into blocks.

* These blocks are all automatically rendered one after the other, but can be rendered separately if needed, in case a single block fails.
* All blocks are needed to cover the ZOV.&#x20;
* The number of blocks can vary from scene to scene, directly depending on the occlusion factor, how much the 3D scene covers the 360 view, or how close you get to some objects.
* Normally, there should only be 2 to 4 blocks.

{% hint style="info" %}
*Note:  There is a safety under "advanced rendering" that sets max blocks to 8 by default. Anything more, you would need to check whether there is a scale issue, a tagging issue, or a Zone of View issue causing the scene to need more blocks.*
{% endhint %}


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