How to calculate height in shader by world_coordinate?

Can you post the entire vertex shader source? If you have a Cesium app with just the tileset and once the tileset is loaded, place a break point here:

https://github.com/AnalyticalGraphicsInc/cesium/blob/master/Source/Scene/Scene.js#L2325

Then, in the console, output the vertex shader text:

commands[j].shaderProgram._vertexShaderText

Thanks,

Dan

OK. I think the problem is that czm_model isn’t set. In the glTF, you need to add a MODEL semantic. From the vertex shader, it looks like there is already a MODELVIEW and PROJECTION semantic with the names u_modelView and u_projection. Once you add a MODEL semantic, use that name, e.g. u_model, to multiply the de-quantized position.