Two Cesium Cartographic Polygon override each other with google Map Tiles

Cesium for Unreal
1

Hi, I’m trying to do the following:

  1. Create one Cesium Cartographic Polygon (CCP) to limit the region that will be displayed in UE5.2. That works fine by itself.
  2. Create other CCP to exclude one bad looking narrow road generated by google maps tiles and replace it with a custom mesh road. The problems start here.

PROBLEM 1:
Once I create the 2nd CCP, add it to the Cesium3DTileset by adding new Raster Overlay and adding polygons of the road CCP, the first raster overlay gets completley ignored. If I re-do the first raster overlay, the 2nd raster overlay gets ignored, and so on…

Is there any way around this?

PROBLEM 2:
The other problem is that the 2nd CCP and Raster Overlay is quite narrow, however, it is doing exactly what I want him to do inside the UE5.2 editor by removing absolutley all the faces of the mesh map that touch the CCP, but when I run the game, excluding faces does not work as expected, and only a few faces disappear as the character progresses through the game and gets closer to the CCP.

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Is there any way to solve this?

2

Every overlay must have a unique Material Layer Key property. Otherwise, they will interfere with each other. In addition, if you need to have two clipping material layers, you’ll need to create a custom material that supports this.

You’ll need to copy the MI_CesiumThreeOverlaysAndClipping and duplicate the Clipping material layer. Give the new layer a different name, e.g. name one Clipping0 and the other Clipping1. Then set the Material Layer Key in each polygon overlay to match one of the material layer names.

You may want to delete some of the other layers you’re not using, like Overlay0,1, and 2, in order to make the material simpler.

1 Like
3

Thank you for your answer to problem #1.
However, I’m a beginner so I dont fully understand how to do this in ue5.
Do you have any step by step guide or video on how to create two Cesium Cartographic Polygon that will do boolean substraction on the google map mesh?
I’m sure this would be a common request in architecture, as one would like to cancel out the unwanted region (rest of the world) and same would like to clip the region where the in focus real estate would be placed with the landscaping.

I know that unreal has the ability to do this on a mesh with Binary Space Partition, I wonder if that would work on the dynamic Cesium mesh?

Also do you know what is causing the problem #2 from my original post?

4

No, we don’t have a step-by-step guide for this, sorry. We appreciate the need for easier and more flexible clipping, but it’s not trivial and it’s not something we’ve been able to invest the necessary time in yet.

I’m not familiar with UE’s Binary Space Partition, so I can’t say if it might work. I suggest trying it and letting us know how it goes.

I suspect problem 2 is caused by having two overlays with the Material Layer Key. Fix that first, and if you’re still having trouble, please describe in more detail what is happening.