problem to draw a primitive with texture

I try to draw a primitive with texture appreance ,but encoutered error: "cannot read property 'center' of undefined ".
I check the cesium code ,it seems the center of boudingsphereCV, but Geometry class have no boudingsphereCV attribute.

code is below:
var geomRoad = new Cesium.Geometry({
        attributes: {
            position: new Cesium.GeometryAttribute({
                componentDatatype: Cesium.ComponentDatatype.FLOAT,
                componentsPerAttribute: 3,
                values: positionsRoad
            , st: new Cesium.GeometryAttribute({
                componentDatatype: Cesium.ComponentDatatype.FLOAT,
                componentsPerAttribute: 2,
                values: UVsRoad
            , normal: new Cesium.GeometryAttribute({
                componentDatatype: Cesium.ComponentDatatype.FLOAT,
                componentsPerAttribute: 3,
                values: normalsRoad
        indices: new Uint16Array([0, 1, 2, 1, 2, 3]),
        primitiveType: Cesium.PrimitiveType.TRIANGLES,
        boundingSphere: Cesium.BoundingSphere.fromVertices(positionsRoad)

    var geoInstanceRoad = new Cesium.GeometryInstance({
        geometry: geomRoad
        , modelMatrix: Cesium.Transforms.eastNorthUpToFixedFrame(originPos)
        //, attributes: {
        // color: Cesium.ColorGeometryInstanceAttribute.fromColor(Cesium.Color.AQUA)
        //id: 'top'
var matRoad = new Cesium.Material({
        fabric: {
            type: 'DiffuseMap',
            uniforms: {
                image: 'data/sketch.png'
var appearanceRoad = new Cesium.MaterialAppearance({
        material: matRoad

    viewer.scene.primitives.add(new Cesium.Primitive({
        geometryInstances: geoInstanceRoad
        , appearance: appearanceRoad

I think you do need to pass a bounding sphere when creating the geometry here. Here’s an example of the RectangleGeometry class creating passing a bounding sphere on creation of the geometry: