Moon Terrain Rendering Tiling Artifacts at 100km Altitude

Cesium for Unreal
1

Hello,

I’m experiencing rendering issues with the Moon terrain in Cesium for Unreal when viewing from higher altitudes, and I’m hoping to get some guidance on resolving this.

I am developing Terrain Relative Navigation (TRN) system for lunar landing simulations. These systems require artifact-free visual representation of the lunar surface across a wide range of altitudes - from approach phase (~100km) down to final descent (~1km and below).

I’m working at longitude = -30.801481°, latitude = -88.3968° (near the lunar south pole), selected because this area has high-resolution terrain data available.

When viewing the lunar surface at 100km altitude, the terrain displays significant visual artifacts that are not present at lower altitudes. Specifically:

Visible tiling patterns and seams: There are prominent rectangular boundaries and geometric patterns overlaid on the terrain that create an unnatural, patchwork appearance
Irregular texture transitions: The surface shows abrupt changes between different texture tiles with clearly visible edges

In contrast, when viewing the same area at 1km altitude, the terrain renders correctly with:
Smooth, natural-looking surface detail
Proper crater definition and topography
No visible tiling seams or artifacts

Screenshots:

Image 1: 100km altitude (showing the artifacts)

Moon_100km
Moon_100km1242×906 207 KB

Image 2: 1km altitude (proper rendering)

Moon_1km
Moon_1km1243×909 214 KB

These artifacts at higher altitudes are problematic for TRN development, as the algorithm need to match them to stored terrain images onboard.

Questions:

Is this a known issue with Moon terrain rendering at higher altitudes?
Are there any tileset settings or configuration options I should adjust?

I’d appreciate any insights or suggestions for resolving this issue. Thank you for your help!

2

Hey @pilgrimstranger, thanks for the detailed writeup and screenshots.

I believe what you’re seeing is a known characteristic of the Cesium Moon Terrain tileset data, rather than a rendering bug. A similar issue was reported near the poles here: Rendering issues at the poles using Cesium Lunar Tiles. Kevin Ring confirmed the artifacts come from source dataset boundaries in the imagery, and unfortunately there’s no client-side fix for them.

At 100km, low-LOD tiles expose these source boundaries. At 1km, higher-resolution data fills the view and hides them.

Given that constraint, here are a couple of mitigation options:

  • Lower the Maximum Screen Space Error on the tileset to force higher-LOD tiles at greater altitudes. This won’t eliminate the seams entirely but should reduce their visibility at the cost of more tile loading.
  • Supply your own high-resolution imagery as a raster overlay for the south pole region (e.g. LROC NAC data if you have access to it). This would let you control the source consistency for the area critical to your TRN work.

You can see the full list of source datasets for Cesium Moon Terrain here: Cesium Moon – Cesium

Let me know if you need more detail on the overlay approach or if there’s anything else I can help with. Cheers!

3

Hi @darcyvdd,

I noticed that this website, which also uses Cesium, does not seem to have issues rendering at the poles:

It would be great if I could do a landing simulation at the pole, since that area have the highest-resolution data.

If this cannot be fixed, could you provide more detail on the overlay approach? I tried using the GeoLandscape Conformer, but so far I have not been able to get it working correctly with the Cesium Moon.

Thank you!