# Incorrect precomputed visibility data

**URL:** <https://forums.unrealengine.com/t/incorrect-precomputed-visibility-data/431753>\
**Category:** Rendering\
**Tags:** precomputed-visibili, unreal-engine, Rendering, UE4, CPP, question\
**Created:** [August 16, 2018, 10:33am UTC](https://forums.unrealengine.com/t/incorrect-precomputed-visibility-data/431753 "2018-08-16T10:33:02Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![anonymous\_user\_c51892cb](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_c51892cb](https://forums.unrealengine.com/u/anonymous_user_c51892cb)\
**Post date:** [August 16, 2018, 10:33am UTC](https://forums.unrealengine.com/t/incorrect-precomputed-visibility-data/431753/1 "2018-08-16T10:33:02Z")

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Hi, my scene consists of a floor on top of which there is a cube wall and a sphere behind the wall. I build the lighting and get the precomputed visibility data. I am running in Debug Editor mode so that I can inspect all the variables properly. I have two questions:

1. Looking at the code, it seems like View.precomputedVisibilityData is an array of 8-bit integers, where each bit corresponds to a static mesh. Bit is 1 if visible else 0. Is my assumption correct ?

2. I put a breakpoint in such a view such that the sphere is completely occluded by the wall. But when I look at View.precomputedVisibilityData (in memory view), it is holding 15, which means all the meshes are visible. If my first assumption is correct, at least one bit should be 0 right ?

I’ve attached the view. Please note that I’ve turned on ‘visualize occluded primitives’, so the green box denotes the sphere which is occluded. Am I missing something ? Can someone explain if I am making the right assumption and looking at the data correctly ?

 ![250626-view.jpg](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/e/6/2e6687bb4c486b3f2449ea68e058637db535d42c.jpeg)

Thanks