You can see the exact problem here Recording #504
Why is the color white when the box is flat? My guess is that it has to do with the lighting I use?
var light = new BABYLON.HemisphericLight('light1', new BABYLON.Vector3(0,1,0), scene);
var box = BABYLON.MeshBuilder.CreateBox("box", {width: 2, height: 2, depth: 2}, scene);
let blackMaterial = new BABYLON.StandardMaterial("blackMaterial", scene);
blackMaterial.diffuseColor = new BABYLON.Color3.FromHexString('#000000');
box.material = blackMaterial;