HighlightLayer rendering issues

I add the ground to the HighlightLayer, and I don’t want the inner mesh to be highlighted together, what should I do?

You should exclude the sphere from the highlight layer:

If there are 100 mesh in my scene, and I highlight a mesh, do I need to exclude the remaining 99 meshes?

Actually, the sphere is not higlighted per see, it’s the camera position that makes look like it:

Here, we can see that it is the highlight of the ground that follows the curve of the sphere.

Having said that, if your mesh is on top of another one, you would have to exclude it from the layer to avoid this artifact.

Or maybe you could try to use the renderOutline property of the mesh instead of a highlight layer?