Tile Boundary Problem

[Shadre]

I have a problem when the opacity of a layer is adjusted towards being transparent. Wherever there are tile boundaries, the tiles bleed downward below the surface of the earth.

I _really_ need help with this because it affects our ability to replace the tool we have deployed using the C# WW baseline. Our users turn down the opacity of the BMNG layer so that they can see data on it, or have another map blend together with it.


I have enlosed two images one showing the texture boundary from far out above North America, where the BMNG layer is at a 0.3 opacity with the "setOpacity" call. The second image is deeper in on a four way tile boundary showing signifigant artifacting among tiles.

[patmurris]

This is a common issue with opacity and geometry tiles 'skirts'. The trick is to have at least one non transparent layer like BMNG on top of which you can have layers with an opacity less then one.

[Shadre]

Thanks! I think we can produce a black layer(w/ 0 alpha), since our guys want to alpha down the BMNG layer as well.

[Shadre]

Is the issue caused by the mesh being imperfect, or does the mesh actually bend down at the intersection on purpose?

[patmurris]

The skirts are part of the surface geometry tiles and are intended to fill the inevitable seams that appear at the junction between tiles of different resolution.

This is a common issue with non continuous terrain meshes - tiled ones in this case. You find skirts, struts, walls - depending how you name them, in WWJ, WW.Net, GE and many other 3D terrain visualization tools.