Radial Disc terrain

I’d like to use something like the cartographic polygon however for it to be a circle rather than a poly. Is there a way to do this either with the cartographic polygon or with the terrain shaders? It’s relatively easy to make a circular disc shader with a regular material graph however applying it into the Cesium material layer system is more challenging.

Any thoughts on best way to do this?

Also, it would be great if this disc could be updated at runtime, eg via a material parameter etc and it doesn’t look like cartographic polys necessarily support updates at runtime.

There’s nothing built in to do this. You either need to customize the shader (perhaps not too hard once you grasp UE’s Material Layer system), or write some code to generate polygon points in a circular shape. The advantage of the latter is that tiles on the wrong side of the circle can be excluded from loading completely, if desired. The disadvantage is that the shape is converted to a raster overlay, which means that runtime changes are possible but slow because textures need to be regenerated.

Thanks. That’s really useful to know. Possibly some combination of a scripted larger tile boundary controller by cartographic polygons and a shader based approach will help balance out performance and speed.

Guess I’ll have to get my head into the material layer system.

I made a cartographic polygon into a circle (roughly) by adding more spline points and reshaping it. Not sure if that makes it any more or less updateable at runtime or not, my use case doesn’t require it.