# How to ensure that when the camera does not roam through the walls of the building model？

**URL:** <https://community.cesium.com/t/how-to-ensure-that-when-the-camera-does-not-roam-through-the-walls-of-the-building-model/4172>\
**Category:** CesiumJS\
**Created:** [May 31, 2016, 12:34pm UTC](https://community.cesium.com/t/how-to-ensure-that-when-the-camera-does-not-roam-through-the-walls-of-the-building-model/4172 "2016-05-31T12:34:23Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![snakesep11](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@snakesep11](https://community.cesium.com/u/snakesep11)\
**Post date:** [May 31, 2016, 12:34pm UTC](https://community.cesium.com/t/how-to-ensure-that-when-the-camera-does-not-roam-through-the-walls-of-the-building-model/4172/1 "2016-05-31T12:34:23Z")

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Hi all,  
I want to show a 3D architectural scene.I had some difficulties.  
1、How to ensure that when the camera does not roam through the walls of the building model？  
2、How to get the height of the surface of the model？

Can someone give me some tips? be deeply grateful！