Extension Autodesk Forge: My control panel doesn't connect to the model after adding my own extension to the package

I used this package (https://github.com/petrbroz/forge-iot-extensions-demo). After that, I added my own extension code (RobotExt.js). The Control panel and Icon of the my extension were added to the Autodesk Forge website. But unfortunately, the control panel doesn't work.

There are these errors:

This is the source code of the my extension file:

class RobotExtension extends Autodesk.Viewing.Extension {
    constructor(viewer, options) {
        super(viewer, options);
        this.viewer = viewer;
        //this.tree = null;
        this.tree = this.viewer.model.getData().instanceTree;
        this.defaultState = null;
        this.customize = this.customize.bind(this);
        this.createUI = this.createUI.bind(this);
        this.setTransformation = this.setTransformation.bind(this);
        this.getFragmentWorldMatrixByNodeId = this.getFragmentWorldMatrixByNodeId.bind(this);
        this.assignTransformations = this.assignTransformations.bind(this);
        this.findNodeIdbyName = this.findNodeIdbyName.bind(this);
    }

    load() {
        console.log('RobotExtension is loaded!');
        this.createUI();
        this.setTransformation();

        return true;
    }
    unload() {
        console.log('RobotExtension is now unloaded!');
        this.viewer.restoreState(this.defaultState);

        return true;
    }

    setTransformation() {
        let tree = this.tree;
    
        /* ====================== right 0 ================= */
        let ID_BaseRod = 4806;
        let ID_LowerArmBody = 4806;

        let Pivot_BaseRod = new THREE.Mesh(new THREE.BoxGeometry(20, 20, 20), new THREE.MeshBasicMaterial({ color: 0xff0000 }));
        let Position_BaseRod = this.getFragmentWorldMatrixByNodeId(ID_BaseRod).matrix[0].getPosition().clone();
        //print the returned value from getFragmentWorldMatrixByNodeId method and using this we can inspect the....
        // output of the fucntion(method) whether working or not
        console.log(Position_BaseRod);
        //console.log(position);
        Pivot_BaseRod.position.x = 0;
        Pivot_BaseRod.position.y = Position_BaseRod.y;
        Pivot_BaseRod.position.z = Position_BaseRod.z-2.84;
        viewer.impl.scene.add(Pivot_BaseRod);

        let Helper_LowerArmBody = new THREE.Mesh();
        let Position_LowerArmBody = this.getFragmentWorldMatrixByNodeId(ID_LowerArmBody).matrix[0].getPosition().clone();
        Helper_LowerArmBody.position.x = - Position_LowerArmBody.x + Math.abs(Position_LowerArmBody.x - Pivot_BaseRod.position.x);
        Helper_LowerArmBody.position.y = - Position_LowerArmBody.y + Math.abs(Position_LowerArmBody.y - Pivot_BaseRod.position.y);
        Helper_LowerArmBody.position.z = - Position_LowerArmBody.z + Math.abs(Position_LowerArmBody.z - Pivot_BaseRod.position.z);
        Pivot_BaseRod.add(Helper_LowerArmBody);
        console.log(Position_LowerArmBody);

        
         // /* ====================== right 1  ================= */
        let ID_BaseRod1 = 4813;
        let ID_LowerArmBody1 = 4813;

        let Pivot_BaseRod1 = new THREE.Mesh(new THREE.BoxGeometry(0.1, 0.1, 0.1), new THREE.MeshBasicMaterial({ color: 0xff0000 }));
        let Position_BaseRod1 = this.getFragmentWorldMatrixByNodeId(ID_BaseRod1).matrix[0].getPosition().clone();
        //print the returned value from getFragmentWorldMatrixByNodeId method and using this we can inspect the....
        // output of the fucntion(method) whether working or not
        console.log(Position_BaseRod1);
        Pivot_BaseRod1.position.x = 0;
        Pivot_BaseRod1.position.y = Position_BaseRod1.y;
        Pivot_BaseRod1.position.z = Position_BaseRod1.z-2.84;
        viewer.impl.scene.add(Pivot_BaseRod1);

        let Helper_LowerArmBody1 = new THREE.Mesh();
        let Position_LowerArmBody1 = this.getFragmentWorldMatrixByNodeId(ID_LowerArmBody1).matrix[0].getPosition().clone();
        Helper_LowerArmBody1.position.x = - Position_LowerArmBody1.x + Math.abs(Position_LowerArmBody1.x - Pivot_BaseRod1.position.x);
        Helper_LowerArmBody1.position.y = - Position_LowerArmBody1.y + Math.abs(Position_LowerArmBody1.y - Pivot_BaseRod1.position.y);
        Helper_LowerArmBody1.position.z = - Position_LowerArmBody1.z + Math.abs(Position_LowerArmBody1.z - Pivot_BaseRod1.position.z);
        Pivot_BaseRod1.add(Helper_LowerArmBody1);
        console.log(Position_LowerArmBody1);

       
         // /* ====================== right 2 ================= */
        let ID_BaseRod2 = 4820;
        let ID_LowerArmBody2 = 4820;

        let Pivot_BaseRod2 = new THREE.Mesh(new THREE.BoxGeometry(0.1, 0.1, 0.1), new THREE.MeshBasicMaterial({ color: 0xff0000 }));
        let Position_BaseRod2 = this.getFragmentWorldMatrixByNodeId(ID_BaseRod2).matrix[0].getPosition().clone();
        //print the returned value from getFragmentWorldMatrixByNodeId method and using this we can inspect the....
        // output of the fucntion(method) whether working or not
        console.log(Position_BaseRod2);
        Pivot_BaseRod2.position.x = 0;
        Pivot_BaseRod2.position.y = Position_BaseRod2.y;
        Pivot_BaseRod2.position.z = Position_BaseRod2.z-2.84;
        viewer.impl.scene.add(Pivot_BaseRod2);

        let Helper_LowerArmBody2 = new THREE.Mesh();
        let Position_LowerArmBody2 = this.getFragmentWorldMatrixByNodeId(ID_LowerArmBody2).matrix[0].getPosition().clone();
        Helper_LowerArmBody2.position.x = - Position_LowerArmBody2.x + Math.abs(Position_LowerArmBody2.x - Pivot_BaseRod2.position.x);
        Helper_LowerArmBody2.position.y = - Position_LowerArmBody2.y + Math.abs(Position_LowerArmBody2.y - Pivot_BaseRod2.position.y);
        Helper_LowerArmBody2.position.z = - Position_LowerArmBody2.z + Math.abs(Position_LowerArmBody2.z - Pivot_BaseRod2.position.z);
        Pivot_BaseRod2.add(Helper_LowerArmBody2);
        console.log(Position_LowerArmBody2);

         // /* ====================== right 3 ================= */
        let ID_BaseRod3 = 4827;
        let ID_LowerArmBody3 = 4827;

        let Pivot_BaseRod3 = new THREE.Mesh(new THREE.BoxGeometry(0.1, 0.1, 0.1), new THREE.MeshBasicMaterial({ color: 0xff0000 }));
        let Position_BaseRod3 = this.getFragmentWorldMatrixByNodeId(ID_BaseRod3).matrix[0].getPosition().clone();
        //print the returned value from getFragmentWorldMatrixByNodeId method and using this we can inspect the....
        // output of the fucntion(method) whether working or not
        console.log(Position_BaseRod3);
        Pivot_BaseRod3.position.x = 0;
        Pivot_BaseRod3.position.y = Position_BaseRod3.y;
        Pivot_BaseRod3.position.z = Position_BaseRod3.z-2.84;
        viewer.impl.scene.add(Pivot_BaseRod3);

        let Helper_LowerArmBody3 = new THREE.Mesh();
        let Position_LowerArmBody3 = this.getFragmentWorldMatrixByNodeId(ID_LowerArmBody3).matrix[0].getPosition().clone();
        Helper_LowerArmBody3.position.x = - Position_LowerArmBody3.x + Math.abs(Position_LowerArmBody3.x - Pivot_BaseRod3.position.x);
        Helper_LowerArmBody3.position.y = - Position_LowerArmBody3.y + Math.abs(Position_LowerArmBody3.y - Pivot_BaseRod3.position.y);
        Helper_LowerArmBody3.position.z = - Position_LowerArmBody3.z + Math.abs(Position_LowerArmBody3.z - Pivot_BaseRod3.position.z);
        Pivot_BaseRod3.add(Helper_LowerArmBody3);
        console.log(Position_LowerArmBody3);

         // /* ====================== right 4 ================= */
        let ID_BaseRod4 = 4834;
        let ID_LowerArmBody4 = 4834;

        let Pivot_BaseRod4 = new THREE.Mesh(new THREE.BoxGeometry(0.1, 0.1, 0.1), new THREE.MeshBasicMaterial({ color: 0xff0000 }));
        let Position_BaseRod4 = this.getFragmentWorldMatrixByNodeId(ID_BaseRod4).matrix[0].getPosition().clone();
        //print the returned value from getFragmentWorldMatrixByNodeId method and using this we can inspect the....
        // output of the fucntion(method) whether working or not
        console.log(Position_BaseRod4);
        Pivot_BaseRod4.position.x = 0;
        Pivot_BaseRod4.position.y = Position_BaseRod4.y;
        Pivot_BaseRod4.position.z = Position_BaseRod4.z-2.84;
        viewer.impl.scene.add(Pivot_BaseRod4);

        let Helper_LowerArmBody4 = new THREE.Mesh();
        let Position_LowerArmBody4 = this.getFragmentWorldMatrixByNodeId(ID_LowerArmBody4).matrix[0].getPosition().clone();
        Helper_LowerArmBody4.position.x = - Position_LowerArmBody4.x + Math.abs(Position_LowerArmBody4.x - Pivot_BaseRod4.position.x);
        Helper_LowerArmBody4.position.y = - Position_LowerArmBody4.y + Math.abs(Position_LowerArmBody4.y - Pivot_BaseRod4.position.y);
        Helper_LowerArmBody4.position.z = - Position_LowerArmBody4.z + Math.abs(Position_LowerArmBody4.z - Pivot_BaseRod4.position.z);
        Pivot_BaseRod4.add(Helper_LowerArmBody4);
        console.log(Position_LowerArmBody4);

         // /* ====================== right 5 ================= */
        let ID_BaseRod5 = 4841;
        let ID_LowerArmBody5 = 4841;

        let Pivot_BaseRod5 = new THREE.Mesh(new THREE.BoxGeometry(0.1, 0.1, 0.1), new THREE.MeshBasicMaterial({ color: 0xff0000 }));
        let Position_BaseRod5 = this.getFragmentWorldMatrixByNodeId(ID_BaseRod5).matrix[0].getPosition().clone();
        //print the returned value from getFragmentWorldMatrixByNodeId method and using this we can inspect the....
        // output of the fucntion(method) whether working or not
        console.log(Position_BaseRod5);
        Pivot_BaseRod5.position.x = 0;
        Pivot_BaseRod5.position.y = Position_BaseRod5.y;
        Pivot_BaseRod5.position.z = Position_BaseRod5.z-2.84;
        viewer.impl.scene.add(Pivot_BaseRod5);

        let Helper_LowerArmBody5 = new THREE.Mesh();
        let Position_LowerArmBody5 = this.getFragmentWorldMatrixByNodeId(ID_LowerArmBody5).matrix[0].getPosition().clone();
        Helper_LowerArmBody5.position.x = - Position_LowerArmBody5.x + Math.abs(Position_LowerArmBody5.x - Pivot_BaseRod5.position.x);
        Helper_LowerArmBody5.position.y = - Position_LowerArmBody5.y + Math.abs(Position_LowerArmBody5.y - Pivot_BaseRod5.position.y);
        Helper_LowerArmBody5.position.z = - Position_LowerArmBody5.z + Math.abs(Position_LowerArmBody5.z - Pivot_BaseRod5.position.z);
        Pivot_BaseRod5.add(Helper_LowerArmBody5);
        console.log(Position_LowerArmBody5);

        //  // /* ====================== left 0 ================= */
        let ID_BaseRod10 = 4851;
        let ID_LowerArmBody10 = 4851;

        let Pivot_BaseRod10 = new THREE.Mesh(new THREE.BoxGeometry(0.1, 0.1, 0.1), new THREE.MeshBasicMaterial({ color: 0xff0000 }));
        let Position_BaseRod10 = this.getFragmentWorldMatrixByNodeId(ID_BaseRod10).matrix[0].getPosition().clone();
        //print the returned value from getFragmentWorldMatrixByNodeId method and using this we can inspect the....
        // output of the fucntion(method) whether working or not
        console.log(Position_BaseRod10);
        Pivot_BaseRod10.position.x = 0;
        Pivot_BaseRod10.position.y = Position_BaseRod10.y;
        Pivot_BaseRod10.position.z = Position_BaseRod10.z-2.84;
        viewer.impl.scene.add(Pivot_BaseRod10);
        console.log(Pivot_BaseRod10);

        let Helper_LowerArmBody10 = new THREE.Mesh();
        let Position_LowerArmBody10 = this.getFragmentWorldMatrixByNodeId(ID_LowerArmBody10).matrix[0].getPosition().clone();
        Helper_LowerArmBody10.position.x =  Position_LowerArmBody10.x + Math.abs(Position_LowerArmBody10.x - Pivot_BaseRod10.position.x);
        Helper_LowerArmBody10.position.y =  -Position_LowerArmBody10.y + Math.abs(Position_LowerArmBody10.y - Pivot_BaseRod10.position.y);
        Helper_LowerArmBody10.position.z =  -Position_LowerArmBody10.z + Math.abs(Position_LowerArmBody10.z - Pivot_BaseRod10.position.z);
        Pivot_BaseRod10.add(Helper_LowerArmBody10);
        console.log(Position_LowerArmBody10);

         // /* ====================== left 1 ================= */
        let ID_BaseRod11 = 4858;
        let ID_LowerArmBody11 = 4858;
        let Pivot_BaseRod11= new THREE.Mesh(new THREE.BoxGeometry(0.1, 0.1, 0.1), new THREE.MeshBasicMaterial({ color: 0xff0000 }));
        let Position_BaseRod11 = this.getFragmentWorldMatrixByNodeId(ID_BaseRod11).matrix[0].getPosition().clone();
        //print the returned value from getFragmentWorldMatrixByNodeId method and using this we can inspect the....
        // output of the fucntion(method) whether working or not
        console.log(Position_BaseRod11);
        Pivot_BaseRod11.position.x = 0;
        Pivot_BaseRod11.position.y = Position_BaseRod11.y;
        Pivot_BaseRod11.position.z = Position_BaseRod11.z-2.84;
        viewer.impl.scene.add(Pivot_BaseRod11);
        console.log(Pivot_BaseRod11);
        let Helper_LowerArmBody11 = new THREE.Mesh();
        let Position_LowerArmBody11 = this.getFragmentWorldMatrixByNodeId(ID_LowerArmBody11).matrix[0].getPosition().clone();
        Helper_LowerArmBody11.position.x =  Position_LowerArmBody11.x + Math.abs(Position_LowerArmBody11.x - Pivot_BaseRod11.position.x);
        Helper_LowerArmBody11.position.y =  -Position_LowerArmBody11.y + Math.abs(Position_LowerArmBody11.y - Pivot_BaseRod11.position.y);
        Helper_LowerArmBody11.position.z =  -Position_LowerArmBody11.z + Math.abs(Position_LowerArmBody11.z - Pivot_BaseRod11.position.z);
        Pivot_BaseRod11.add(Helper_LowerArmBody11);
        console.log(Position_LowerArmBody11);
         // /* ====================== left 2 ================= */
         // /* ====================== left 3 ================= */
         // /* ====================== left 4 ================= */
         // /* ====================== left 5 ================= */
        let ID_BaseRod15 = 4886;
        let ID_LowerArmBody15 = 4886;

        let Pivot_BaseRod15= new THREE.Mesh(new THREE.BoxGeometry(0.1, 0.1, 0.1), new THREE.MeshBasicMaterial({ color: 0xff0000 }));
        let Position_BaseRod15 = this.getFragmentWorldMatrixByNodeId(ID_BaseRod15).matrix[0].getPosition().clone();
        //print the returned value from getFragmentWorldMatrixByNodeId method and using this we can inspect the....
        // output of the fucntion(method) whether working or not
        console.log(Position_BaseRod15);
        Pivot_BaseRod15.position.x = 0;
        Pivot_BaseRod15.position.y = Position_BaseRod15.y;
        Pivot_BaseRod15.position.z = Position_BaseRod15.z-2.84;
        viewer.impl.scene.add(Pivot_BaseRod15);
        console.log(Pivot_BaseRod15);

        let Helper_LowerArmBody15 = new THREE.Mesh();
        let Position_LowerArmBody15 = this.getFragmentWorldMatrixByNodeId(ID_LowerArmBody15).matrix[0].getPosition().clone();
        Helper_LowerArmBody15.position.x =  Position_LowerArmBody15.x + Math.abs(Position_LowerArmBody15.x - Pivot_BaseRod15.position.x);
        Helper_LowerArmBody15.position.y =  -Position_LowerArmBody15.y + Math.abs(Position_LowerArmBody15.y - Pivot_BaseRod15.position.y);
        Helper_LowerArmBody15.position.z =  -Position_LowerArmBody15.z + Math.abs(Position_LowerArmBody15.z - Pivot_BaseRod15.position.z);
        Pivot_BaseRod15.add(Helper_LowerArmBody15);
        console.log(Position_LowerArmBody15);

             // right side
        this.assignTransformations(Helper_LowerArmBody, ID_LowerArmBody);
        this.assignTransformations(Helper_LowerArmBody1, ID_LowerArmBody1);
        this.assignTransformations(Helper_LowerArmBody2, ID_LowerArmBody2);
        this.assignTransformations(Helper_LowerArmBody3, ID_LowerArmBody3);
        this.assignTransformations(Helper_LowerArmBody4, ID_LowerArmBody4);
        this.assignTransformations(Helper_LowerArmBody5, ID_LowerArmBody5);

           // Left side
        this.assignTransformations(Helper_LowerArmBody10, ID_LowerArmBody10);
        this.assignTransformations(Helper_LowerArmBody11, ID_LowerArmBody11);
        this.assignTransformations(Helper_LowerArmBody12, ID_LowerArmBody12);
        this.assignTransformations(Helper_LowerArmBody13, ID_LowerArmBody13);
        this.assignTransformations(Helper_LowerArmBody14, ID_LowerArmBody14);
        this.assignTransformations(Helper_LowerArmBody15, ID_LowerArmBody15);


        /* ====================== Link to controls ================= */

        let baseControlSlider = document.getElementById("baseControl");
        let firstControlSlider = document.getElementById("firstArm");
        let secondControlSlider = document.getElementById("secondArm");
        // let thirdControlSlider = document.getElementById("thirdArm");

        baseControlSlider.oninput = (event) => {
            Pivot_BaseRod.rotation.y = Math.PI/180 * event.target.value;
            Pivot_BaseRod1.rotation.y = Math.PI/180 * event.target.value;
            Pivot_BaseRod2.rotation.y = Math.PI/180 * event.target.value;
            Pivot_BaseRod3.rotation.y = Math.PI/180 * event.target.value;
            Pivot_BaseRod4.rotation.y = Math.PI/180 * event.target.value;
            Pivot_BaseRod5.rotation.y = Math.PI/180 * event.target.value;
            this.assignTransformations(Helper_LowerArmBody, ID_LowerArmBody);
            this.assignTransformations(Helper_LowerArmBody1, ID_LowerArmBody1);
            this.assignTransformations(Helper_LowerArmBody2, ID_LowerArmBody2);
            this.assignTransformations(Helper_LowerArmBody3, ID_LowerArmBody3);
            this.assignTransformations(Helper_LowerArmBody4, ID_LowerArmBody4);
            this.assignTransformations(Helper_LowerArmBody5, ID_LowerArmBody5);
            
            this.viewer.impl.sceneUpdated(true);
        };

        firstControlSlider.oninput = (event) => {
            Pivot_BaseRod10.rotation.y = Math.PI/-180 * event.target.value;
            Pivot_BaseRod11.rotation.y = Math.PI/-180 * event.target.value;
            Pivot_BaseRod12.rotation.y = Math.PI/-180 * event.target.value;
            Pivot_BaseRod13.rotation.y = Math.PI/-180 * event.target.value;
            Pivot_BaseRod14.rotation.y = Math.PI/-180 * event.target.value;
            Pivot_BaseRod15.rotation.y = Math.PI/-180 * event.target.value;

            this.assignTransformations(Helper_LowerArmBody10, ID_LowerArmBody10);
            this.assignTransformations(Helper_LowerArmBody11, ID_LowerArmBody11);
            this.assignTransformations(Helper_LowerArmBody12, ID_LowerArmBody12);
            this.assignTransformations(Helper_LowerArmBody13, ID_LowerArmBody13);
            this.assignTransformations(Helper_LowerArmBody14, ID_LowerArmBody14);
            this.assignTransformations(Helper_LowerArmBody15, ID_LowerArmBody15);
            
            this.viewer.impl.sceneUpdated(true);
        };
        secondControlSlider.oninput = (event) => {
            Pivot_BaseRod.rotation.y = Math.PI/180 * event.target.value;
            Pivot_BaseRod1.rotation.y = Math.PI/180 * event.target.value;
            Pivot_BaseRod2.rotation.y = Math.PI/180 * event.target.value;
            Pivot_BaseRod3.rotation.y = Math.PI/180 * event.target.value;
            Pivot_BaseRod4.rotation.y = Math.PI/180 * event.target.value;
            Pivot_BaseRod5.rotation.y = Math.PI/180 * event.target.value;
            this.assignTra开发者_如何学编程nsformations(Helper_LowerArmBody, ID_LowerArmBody);
            this.assignTransformations(Helper_LowerArmBody1, ID_LowerArmBody1);
            this.assignTransformations(Helper_LowerArmBody2, ID_LowerArmBody2);
            this.assignTransformations(Helper_LowerArmBody3, ID_LowerArmBody3);
            this.assignTransformations(Helper_LowerArmBody4, ID_LowerArmBody4);
            this.assignTransformations(Helper_LowerArmBody5, ID_LowerArmBody5);

        
            Pivot_BaseRod10.rotation.y = Math.PI/-180 * event.target.value;
            Pivot_BaseRod11.rotation.y = Math.PI/-180 * event.target.value;
            Pivot_BaseRod12.rotation.y = Math.PI/-180 * event.target.value;
            Pivot_BaseRod13.rotation.y = Math.PI/-180 * event.target.value;
            Pivot_BaseRod14.rotation.y = Math.PI/-180 * event.target.value;
            Pivot_BaseRod15.rotation.y = Math.PI/-180 * event.target.value;
            this.assignTransformations(Helper_LowerArmBody10, ID_LowerArmBody10);
            this.assignTransformations(Helper_LowerArmBody11, ID_LowerArmBody11);
            this.assignTransformations(Helper_LowerArmBody12, ID_LowerArmBody12);
            this.assignTransformations(Helper_LowerArmBody13, ID_LowerArmBody13);
            this.assignTransformations(Helper_LowerArmBody14, ID_LowerArmBody14);
            this.assignTransformations(Helper_LowerArmBody15, ID_LowerArmBody15);

            this.viewer.impl.sceneUpdated(true);
        };
    }

    findNodeIdbyName(name) {
        let tree = this.tree;
        let nodeList = Object.values(tree.nodeAccess.dbIdToIndex);
        for (let i = 1, len = nodeList.length; i < len; ++i) {
            let node_name = tree.getNodeName(nodeList[i]);
            if (node_name === name) {
                return nodeList[i];
            }
        }
        return null;
    }

    getFragmentWorldMatrixByNodeId(nodeId) {
        let viewer = this.viewer;

        let result = {
            fragId: [],
            matrix: [],
        };
        this.tree.enumNodeFragments(nodeId, function (frag) {

            let fragProxy = viewer.impl.getFragmentProxy(viewer.model, frag);
            let matrix = new THREE.Matrix4();

            fragProxy.getWorldMatrix(matrix);

            result.fragId.push(frag);
            result.matrix.push(matrix);
        });
        return result;
    }

    assignTransformations(ref_obj, nodeId) {
        let viewer = this.viewer;

        ref_obj.parent.updateMatrixWorld();
        var position = new THREE.Vector3();
        var rotation = new THREE.Quaternion();
        var scale = new THREE.Vector3();
        ref_obj.matrixWorld.decompose(position, rotation, scale);

        this.tree.enumNodeFragments(nodeId, function (frag) {
            var fragProxy = viewer.impl.getFragmentProxy(viewer.model, frag);
            fragProxy.getAnimTransform();
            fragProxy.position = position;
            fragProxy.quaternion = rotation;
            fragProxy.updateAnimTransform();
        });
    }
    getAllLeafComponents(callback) {
        this.viewer.getObjectTree(function (tree) {
            let leaves = [];
            tree.enumNodeChildren(tree.getRootId(), function (dbId) {
                if (tree.getChildCount(dbId) === 0) {
                    leaves.push(dbId);
                }  
            }, true);
            callback(leaves);
        });
    }

    customize() {
        this.defaultState = this.viewer.getState();
        this.viewer.restoreState(someViewerState);
        this.viewer.impl.setPostProcessParameter("style", "edging");
        this.viewer.impl.setPostProcessParameter("depthEdges", false);
        this.viewer.setBackgroundColor(255,255,255,255,255,255);
        this.viewer.setGroundShadow(false);
        this.viewer.setGroundReflection(true);
        this.viewer.setTheme("light-theme");
    }

    createUI() {
        this.ui = document.createElement("div");
        this.ui.id = "control_area";
        this.ui.classList.add("docking-panel-container-solid-color-a");
        this.ui.innerHTML = `
            <div id="controlsArea">
                <div><span>Right Side: </span><input type="range" min="0" max="45" value="0" class="slider" id="baseControl"></div>
                <div><span>Left Side: </span><input type="range" min="0" max="45" value="0" class="slider" id="firstArm"></div>
                <div><span>All: </span><input type="range" min="0" max="45" value="0" class="slider" id="secondArm"><type="range" min="-45" max="0" value="0" class="slider" id="secondArm"></div>
            </div>
        `;

        let panel = this.panel;
        let viewer = this.viewer;
        // check https://forge.autodesk.com/blog/extension-skeleton-toolbar-docking-panel
        let toolbarButtonRobot = new Autodesk.Viewing.UI.Button('RobotControl');

        if (panel == null) {
            panel = new RobotControlPanel(viewer, viewer.container,
                'controlPanel', 'Kinetic Ventilation Window', {"innerDiv":this.ui});
        }

        toolbarButtonRobot.onClick = (e) => {

            panel.setVisible(!panel.isVisible());
        };

        toolbarButtonRobot.addClass('toolbarButtonRobot');
        toolbarButtonRobot.setToolTip('Show/Hide Robot Controls');

        // SubToolbar
        this.subToolbar = new Autodesk.Viewing.UI.ControlGroup('ExtensionRobotControlToolbar');
        this.subToolbar.addControl(toolbarButtonRobot);

        this.viewer.toolbar.addControl(this.subToolbar);
    }
}

Autodesk.Viewing.theExtensionManager.registerExtension('RobotExtension',
    RobotExtension);

// *******************************************
// Robot Control Panel
// *******************************************
function RobotControlPanel(viewer, container, id, title, options) {
    this.viewer = viewer;

    Autodesk.Viewing.UI.DockingPanel.call(this, container, id, title, options);

    this.container.classList.add('docking-panel-container-solid-color-a');
    this.container.id = "robotControlPanelContainer";

    this.container.appendChild(options.innerDiv);
}
RobotControlPanel.prototype = Object.create(Autodesk.Viewing.UI.DockingPanel.prototype);
RobotControlPanel.prototype.constructor = RobotControlPanel;

const someViewerState = {
    "seedURN": "dXJuOmFkc2sub2JqZWN0czpvcy5vYmplY3Q6YWIxMjM0LzA5MjlDYWJsZVR5cGUucnZ0",
    "objectSet": [
        {
            "id": [],
            "isolated": [],
            "hidden": [],
            "explodeScale": 0,
            "idType": "lmv"
        }
    ],
    "viewport": {
        "name": "",
        "eye": [
            204.48330126505937,
            100.3164039523009,
            182.73839807077565
        ],
        "target": [
            1.0011920928955078,
            2.052783966064453,
            0
        ],
        "up": [
            -0.25157238314283936,
            0.9410997291372207,
            -0.2259261734675335
        ],
        "worldUpVector": [
            0,
            1,
            0
        ],
        "pivotPoint": [
            1.0011920928955078,
            2.052783966064453,
            0
        ],
        "distanceToOrbit": 290.6097553342371,
        "aspectRatio": 1.3423517169614985,
        "projection": "perspective",
        "isOrthographic": false,
        "fieldOfView": 22.61986532341139
    },
    "renderOptions": {
        "environment": "(Custom: Model defined)",
        "ambientOcclusion": {
            "enabled": true,
            "radius": 5.945260721973842,
            "intensity": 0.4
        },
        "toneMap": {
            "method": 1,
            "exposure": -8.974,
            "lightMultiplier": -1e-20
        },
        "appearance": {
            "ghostHidden": true,
            "ambientShadow": true,
            "antiAliasing": true,
            "progressiveDisplay": true,
            "swapBlackAndWhite": false,
            "displayLines": true,
            "displayPoints": true
        }
    },
    "cutplanes": []
};

There was error for limitation character in Stackoverflow I had to delete some part of my code. (Left 2, Left 3 , Left 4)

In the setTransformation method of your extension class, you have the following line of code:

viewer.impl.scene.add(Pivot_BaseRod1);

The viewer variable is not defined, however. The line of code should instead look like this:

this.viewer.impl.scene.add(Pivot_BaseRod1);