# Demoting a region of terrain and making it transparent

**URL:** <https://community.cesium.com/t/demoting-a-region-of-terrain-and-making-it-transparent/718>\
**Category:** CesiumJS\
**Created:** [September 15, 2013, 10:49pm UTC](https://community.cesium.com/t/demoting-a-region-of-terrain-and-making-it-transparent/718 "2013-09-15T22:49:21Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![chihhaoyu827](https://avatars.discourse-cdn.com/v4/letter/c/0ea827/32.png) [@chihhaoyu827](https://community.cesium.com/u/chihhaoyu827)\
**Post date:** [September 15, 2013, 10:49pm UTC](https://community.cesium.com/t/demoting-a-region-of-terrain-and-making-it-transparent/718/1 "2013-09-15T22:49:21Z")

</div>

Hi all,

Is me again, just want to ask about the newer terrain feature.

I am visualisation the distributions of water aquifer's, therefore, some of the 3D primitives are displayed beneath the globe.

As a result I need to manually set an area (simple as a rectangular region) and demote that region to make a hole, so that the primitives can be seen.

And the other way is to set the surface transparent limited to that region.

Now I have noticed the terrain tutorial and its reference documentation, but it does not tell me much how am I going to create such effect manually.

Can anyone shed some light to this issue?

Thank you

Dave

---

<div class="post-metadata">

**Author:** ![Kevin\_Ring](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/kevin_ring/32/2003_2.png) [@Kevin\_Ring](https://community.cesium.com/u/Kevin_Ring)\
**Post date:** [September 16, 2013, 3:55pm UTC](https://community.cesium.com/t/demoting-a-region-of-terrain-and-making-it-transparent/718/2 "2013-09-16T15:55:25Z")

</div>

Hi Dave,

Cesium doesn’t have any built-in support for that. This old post may point you in the direction of implementing a custom solution:

[https://groups.google.com/d/topic/cesium-dev/TPiWWF8TNdM/discussion](https://groups.google.com/d/topic/cesium-dev/TPiWWF8TNdM/discussion)

Kevin

---

<div class="post-metadata">

**Author:** ![chihhaoyu827](https://avatars.discourse-cdn.com/v4/letter/c/0ea827/32.png) [@chihhaoyu827](https://community.cesium.com/u/chihhaoyu827)\
**Post date:** [September 17, 2013, 12:41am UTC](https://community.cesium.com/t/demoting-a-region-of-terrain-and-making-it-transparent/718/3 "2013-09-17T00:41:00Z")

</div>

Hi Kevin,

Thanks.

Dave