Is it possible to change individual 3D building height in 3D tiles interactively?

CesiumJS
1

Is it possible to change individual 3D building height in 3D tiles interactively?

For instance, click building -> show popup and inside of the popup allow the user to enter desired height -> change building height

I know the same can be achieved using geojson/czml, but I would like to confirm it before exploring the 3D tiles.

Thank you,

Makiko

2

This is not easily possible at the moment, and is a difficult operation to perform since buildings are often batched together. Though I could see this being done with a custom shader that utilizes batch_ids in a some way…

3

Hi Sean,

Thank you so much for your quick response. It sounds like it is possible, but it isn’t easy to do so. What about using glTF for individual buildings (may be about 100 buildings) instead of 3D tiles?

Thank you,

Makiko

4

Using individual buildings will definitely make it a lot easier to adjust the height by controlling the scale.

5

Hi Sean,

How to control only height with scale? Is there a way to adjust only height? I looked at CZML Model sandcastle example with my own data and tested it.

var czml = [{

“id” : “document”,

“name” : “CZML Model”,

“version” : “1.0”

}, {

“id” : “01”,

“name” : “Building 1”,

“position” : {

“cartographicDegrees” : [-78.64457953412446, 35.779551666457692, 0]

},

“model”: {

“gltf” : “…/SampleData/models/CGA/ID_1.glb”,

“scale” : 0.30480060960121924 * 10, // -->** uniform scale change. Is there way to adjust only height?

“minimumPixelSize”: 128

}

}];

var viewer = new Cesium.Viewer(‘cesiumContainer’);

var promise = viewer.dataSources.add(Cesium.CzmlDataSource.load(czml));

Thank you,

Makiko

6

For non-uniform scale you can use the “nodeTransformations” property if you have the name of the root node in the glTF file.

var entity = viewer.entities.add({
    name : url,
    position : position,
    orientation : orientation,
    model : {
        uri : url,
        nodeTransformations : {
            root : {
                scale : new Cesium.Cartesian3(1.0, 1.0, 10.0)
            }
        }
    }
});

``

Another thing to try is using the primitive API and setting the model’s modelMatrix directly like

model.modelMatrix = Cesium.Matrix4.fromScale(new Cesium.Cartesian3(1.0, 1.0, 10.0));

``

which will work regardless of the gltf node names.

7

Hi Sean,

Thank you so much for your help!! I thought it would be better for me to use Entity than Primitive API so I used the first example. It took for while to figure out, but I was able to change the building height after finding the answer for “root”. The link below (see Sean’s answer "nodeTransformations references the glTF node’s “name” … ) helped me to figure out. I converted Collada files to glTF using COLLADA2GLTF converter and all glTF file node names were “Y_UP_Transform”.

https://groups.google.com/forum/#!topic/cesium-dev/Eqttp9vcR90

Thank you, Sean!

Makiko

8

Ah yeah I should have linked that post myself. I’m glad its working for you now!