Render sphere function

rendersphere.swift

    func renderSphere() {
        let geometry:SCNGeometry = SCNSphere(radius: 0.05) //units, meters
        let geometryNode = SCNNode(geometry: geometry)
        geometryNode.position = SCNVector3(x:0.0, y:0.0, z:0.0)
        geometryNode.geometry?.firstMaterial?.diffuse.contents = UIColor.green
        sceneView.scene.rootNode.addChildNode(geometryNode)
    }