usage of lightColor on Cesium3DTileset to brighten models

CesiumJS
1

I am having a similar issue reported here (https://github.com/AnalyticalGraphicsInc/cesium-ion-community/issues/73) where the dev wanted to brighten some tilesets. The advice given was to modify the lightColor attribute. This particular attribute is not well documented, but I tried modifying the values similar to their example and I am seeing no effect.

tileset.lightColor = new Cesium.Cartesian3(3, 2.8, 2.4);

I have also tried creating a Cesium3DTileStyle to modify the colors to have max alpha, and that also has no effect.

tileset.style = new Cesium.Cesium3DTileStyle({ color: { evaluateColor : function(feature, result) {
if (feature && feature.color)
return new Cesium.Color(feature.color.red,feature.color.green,feature.color.blue,1);
else
return Cesium.Color.WHITE;
}
}});

Any guidance or other things I can try?

Thanks

2

Thanks for following up! I posted some thoughts on the GitHub issue, perhaps Sean might have an idea:

https://github.com/AnalyticalGraphicsInc/cesium-ion-community/issues/73#issuecomment-479681820

Did you tile your models on Cesium ion? Did you select the photogrammetry setting when tiling?

3

We did not tile the models on Cesium Ion, we have another product creating our tilesets. I will see if I can find out what settings they use, but is there something in the tileset json I can look at that would indicate those settings?

4

In the same directory as your tileset.json, you should see additional folder that eventually contain b3dm files. This is a container for a glTF/glb.

There’s a 3D Tiles inspector on Cesium ion that you could drag a tile into, but it’s currently beta-only I believe. I think you’d have to convert the b3dm to glb using this tool:

https://github.com/AnalyticalGraphicsInc/3d-tiles-tools/tree/master/tools#b3dmtoglb

And then use the glTF viewer in VS code to convert the glb to glTF and look at it:

https://github.com/AnalyticalGraphicsInc/gltf-vscode#gltf-tools-extension-for-visual-studio-code

Then I’d look for the materials node, and see if it’s using the UNLIT extension.

Can I ask what product you’re using to create the tileset? It might also be possible to tweak the material setting during export (when it converts the source format you give it to glTF) to make it brighter. Let me know if that helps.

5

Omar, thanks for your responses.

I was able to convert one of the b3dm to glb. However the gltf extension for vs code didn't work since the resulting glb was glb version 1 (it requires version 2).

I was able to convert to gltf using assimp, and the materials node doesn't have the UNLIT extension:

"materials": {
        "effect0": {
            "values": {
                "ambient": [
                    0.0,
                    0.0,
                    0.0,
                    1.0
                ],
                "diffuse": "texture",
                "specular": [
                    0.32999998331069949,
                    0.32999998331069949,
                    0.32999998331069949,
                    1.0
                ],
                "emission": [
                    0.0,
                    0.0,
                    0.0,
                    1.0
                ],
                "shininess": 10.0
            }
        }
    }

I am not sure if I can share what product we are creating our tilesets with, waiting on someone to answer that...

6

In any case, I'm 90% sure we are using photogrammetry tilesets, just waiting on confirmation for that. If that's the case, then it appears based on your comment on github that the lightColor won't work to brighten the 3d tilesets. Maybe the Cesium documentation for lightColor on Cesium3DTileset could be updated to reflect that?
  https://cesiumjs.org/Cesium/Build/Documentation/Cesium3DTileset.html#lightColor