White 3d tiles very dark

Hi, I’ve created white 3D Tiles but they are visualized very dark/gray (even when changing time of day). Why do the models look so dark? How to draw them bright white?

Demo https://bertt.github.io/cesium_issues/dark/

Glb (https://bertt.github.io/cesium_issues/dark/tiles/content/2_0_1.glb)

The B3DM contains a GLB with

  "materials" : [
      "doubleSided" : true,
      "pbrMetallicRoughness" : { }
      "doubleSided" : true,
      "pbrMetallicRoughness" : {
        "metallicFactor" : 0,
        "roughnessFactor" : 0.501960813999176

The empty pbrMetallicRoughness of the material causes the default values to be used, and the default metallicFactor is 1, according to the specification.

(I somehow think that this … is undesirable, and have the impression that some viewers do not obey this, but… would have to try it out in detail, and look up the implemementation of each viewer…)

So the default value of 1.0 should cause objects to appear very dark. For example, consider the upper right sphere in this MetalRoughSpheresNoTextures sample model screenshot:

(The base color there is (0.6, 0.6, 0.6), but for (1,1,1) (white) the effect would be the same - namely that of appearing much darker than one would expect).

Changing the material definition to set the metallicFactor to 0 should fix this:

      "doubleSided": true,
      "pbrMetallicRoughness": {
        "metallicFactor": 0

Cesium Forum 26208 metallic issue

(The lighting still depends on the time of day, of course, but in broad daylight, the objects should appear white then…)

1 Like

ah thanks a lot! Fixed it here https://bertt.github.io/cesium_issues/dark/fixed/

three.js has defaults 0.0 for metallic, 1.0 for roughness three.js docs

using these defaults in Cesium would prevent this kind of issues, maybe an idea?