transparency on image rendered as polygon

Hello All,

Just wanted to know whether cesium supports transparency/alpha for groundOverlay/image

the sample czml for the same is as given below using ImageMaterialProperty : please let me know whether alpha can be applied on image.

"polygon":{
      "positions":{
        "cartographicDegrees":[
          -122.38607211584785,37.79088473344126,0,-122.38607211584785,37.789267771712346,0,-122.38768907757675,37.789267771712346,0,-122.38768907757675,37.79088473344126,0,-122.38607211584785,37.79088473344126,0
        ]
      },
      "show":true,
    "material":{
        "image":{
          "image":"images/add.png"
        }
      },
    
      "fill":true
}

thanks,
neel

Hello Neel,

Currently, there isn’t a way to configure the transparency on an image material. We have this issue on GitHub to fix that:https://github.com/AnalyticalGraphicsInc/cesium/issues/2484

Most other materials can be made transparent using the alpha value in color.rgba.

Best,

Hannah

We mitigated this issue in our application at our service that streams CZML. The actual image is modified in java and sent across the wire already rendered with a specified alpha value.

We ran into an issue where we would see, for a split second, the white background before the image is loaded onto the polygon. Is there is way to specify an initial no fill or transparent polygon?

This is a long-standing bug in Cesium.

See https://github.com/AnalyticalGraphicsInc/cesium/issues/1640 for more details.