Distant objects disappearing – offshore wind turbines 30 km from shore

Cesium ion
1

Hi everyone, I’m new here!

I’m working on a project where I need to visualize an offshore wind farm from the coastline, located approximately 30 km away.

One of my first concerns was whether the wind turbines would still load and remain visible from that distance. Unfortunately, that concern turned out to be justified — as I move the camera farther away, the objects eventually disappear from view.

Has anyone dealt with a similar issue or found a solution for keeping distant models visible? Ideally, I need the wind turbines to remain visible from the shore at a distance of around 30 km.

Any advice would be greatly appreciated. Thanks!

3

This was opened in the ‘Cesium ion’ section. The solution might (to some extent) depend on the runtime engine (i.e. CesiumJS, CesiumForUnreal, etc). Some details may also depend on the structure of the tileset - i.e. low-level technical aspects of the ‘tileset.json’ that was generated.

But very roughly:

The decision of whether something is rendered or not solely depends on the ‘geometric error’ of the tileset and the ‘maximum screen space error’ in the runtime engine. (That’s not true, but let’s ignore things like frustum/fog/horizon culling for now).

Assuming that this is about CesiumJS:

One path to a solution could be to decrease the maximumScreenSpaceError value. So as a first shot, you could try this:

  const tileset = await Cesium.Cesium3DTileset.fromIonAssetId(YOUR_ASSET_ID, {
    maximumScreenSpaceError: 8.0
  });
  viewer.scene.primitives.add(tileset);

The default for the maximumScreenSpaceError is 16.0, and you can try to reduce it to 8.0 (or even lower) to see whether the objects are then still displayed at large distances.

(If this doesn’t help, it may be necessary to investigate a few more details about the data set…)

4

I’ve seen similar behavior with Cesium.

For a case like this, I’d first check whether the turbines disappear at a consistent camera distance. If they do, it may be useful to look at how the tileset was generated, particularly the geometric error and bounding volumes for the turbine tiles.

Since the turbines are relatively small compared with the overall scene at 30 km, the way the tiles are structured can make quite a difference to how they are represented at that distance.

If you’re using CesiumJS, I’d be interested to know how the wind farm was converted into the tileset and whether the turbines are individual tiles or part of larger tiles.

5

I’m using just Cesium story (first time at all). I tried to do something in cesium JS but failed.

I can share viewer link ( Cesium Stories ) to better show my question.

I have a simple FBX model of a wind turbine. Each turbine is stored as a separate file because when I import all the turbines into a single file, the geometry becomes distorted.

I’ve created approximate viewpoints from which I’d like to view the wind farm. When I raise the camera higher, the geometry is visible, but as soon as I move the viewpoint to a lower position, the objects simply disappear.

In some cases, a few turbines were visible from the lower viewpoints, but later they disappeared again.

Is there a way to resolve this in Cesium Stories, or is CesiumJS the only option?

6

I had a short look at the story. Stories are a bit more difficult to debug than Sandcastles. But from a quick test, something is fishy here: It shows the turbines on slide 3, but not on slide 4, even though (at the beginning of the transition) the view configuation is basically the same. Could it be that slide 4 simply does not contain the turbines?

7

This is the issue I’m trying to resolve. The turbines are visible from certain viewing angles, but as I change the camera position, they either disappear or reappear.

The turbine models are enabled in all slides, but they are not always visible. If I zoom in toward the wind farm, the models eventually appear, but I need them to remain visible at all times, regardless of the viewing distance or camera position.

In the first slide, part of the turbines are visible from the top view. However, this also seems to depend on the screen size: when I view the same camera position on a larger monitor, some turbines are visible, while on a smaller monitor they are not.

In the second view, the FBX turbine models are not visible. What is visible there is a point cloud. To check whether the viewing angle itself was the problem, I added a LAZ file, and the point cloud displays correctly from this angle. There are no visibility issues with the point cloud — it remains visible at all times.