# billboard vision level, questions about tiles

**URL:** <https://community.cesium.com/t/billboard-vision-level-questions-about-tiles/3811>\
**Category:** CesiumJS\
**Created:** [March 4, 2016, 9:26pm UTC](https://community.cesium.com/t/billboard-vision-level-questions-about-tiles/3811 "2016-03-04T21:26:28Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![luanantonio](https://avatars.discourse-cdn.com/v4/letter/l/cc9497/32.png) [@luanantonio](https://community.cesium.com/u/luanantonio)\
**Post date:** [March 4, 2016, 9:26pm UTC](https://community.cesium.com/t/billboard-vision-level-questions-about-tiles/3811/1 "2016-03-04T21:26:28Z")

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I am using billboards in my application for the quadtree level, just have a question, how do I know the amount of tiles are loaded by level?

var = viewer.scene.globe.\_surface.\_tilesToRender tiles;

I'm working on the clock event cesium  
viewer.clock.onTick.addEventListener (function () {// check levels and applies});

(Basically verifies level and puts true view on the billboard, if you change your level does the same thing)

if I knew how many tiles would be charged per level, without having to use timeouts and intervals and use own methods, I believe it would be better ...  
because I am using data from the database and be always comparing tiles is no loss of performance ... is there any method or calculation that I can know the amount of tiles that will be rendered in the scene?

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<div class="post-metadata">

**Author:** ![luanantonio](https://avatars.discourse-cdn.com/v4/letter/l/cc9497/32.png) [@luanantonio](https://community.cesium.com/u/luanantonio)\
**Post date:** [March 4, 2016, 9:29pm UTC](https://community.cesium.com/t/billboard-vision-level-questions-about-tiles/3811/2 "2016-03-04T21:29:44Z")

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var tiles = viewer.scene.globe.\_surface.\_tilesToRender;